This is an appeal from a judgment and order dated February 19, 1981, of the Waukesha county circuit court Judge Neal P. Nettesheim, denying the petition of George S. Melentowich which sought relief by a writ of habeas corpus. Melentowich challenges the order directing his return to the state of California. The court of appeals certified this case to us on January 21, 1982, and we granted certification on February 8, 1982, because it involves an issue1 of first impression in this state.
*376On May 29, 1974, petitioner was found not guilty by reason of insanity by the superior court of the state of California of several crimes committed while he was a walkaway mental patient. The crimes were second-degree murder of a Trinity county deputy sheriff and two counts of assault with a deadly weapon. That court ordered petitioner committed to a California state psychiatric hospital for treatment until such time as his sanity was restored.
On July 27, 1979, Melentowieh left the California state hospital without permission, and he testified that he left California on or about July 28, 1979. After going to Reno, Nevada, Chicago, and New York, petitioner came to Wisconsin on or about December 17, 1979, where his mother resides. A week after petitioner absconded, the California superior court issued a bench warrant for his apprehension and return to the California psychiatric hospital.
In April of 1980, the petitioner was arrested in Wau-kesha county on charges of disorderly conduct. After discovering that petitioner was a walkaway mental patient from the California hospital, Wisconsin authorities contacted California authorities on approximately April 8, 1980, to inquire about his status. California authorities confirmed that petitioner was a walkaway mental patient from California state hospital and was considered “extremely dangerous,” particularly when he was not bn medication. California state hospital personnel stated that through the years petitioner has walked away from institutions bn numerous occasions, but he has always been apprehended within the state of California and returned to the hospital. California hospital personnel stated that, because petitioner absconded to Wisconsin, in order to return him to the hospital “the situation was more complicated” because of extradition red tape.
*377The Waukesha county district attorney elected to pursue petitioner’s civil commitment rather than a criminal prosecution for disorderly conduct. On May 30, 1980, Waukesha county circuit court Judge Willis J. Zick ordered petitioner committed to the custody of the Community Board of Waukesha County/Department of Health and Social Services for involuntary treatment at Mendota Mental Health Institute for a six-month period. In October of 1980, petitioner was transferred to North-view Hospital, and in December of that year he was granted a conditional transfer from Northview to live with his mother in Hartland, Wisconsin, and receive outpatient treatment at Northview Hospital.
On Nevember 28, 1980, approximately seven and one-half months after California was informed of petitioner's presence in Wisconsin, Governor Brown of California executed a demand for petitioner’s return to that state pursuant to secs. 51.82 and 51.83, Stats. Governor Dreyfus signed a warrant for petitioner’s arrest for extradition on February 2, 1981. Following his arrest, Melento-wich petitioned the court for a writ of habeas corpus, contending extradition proceedings were unlawful because he was not subject to criminal extradition (escape from a mental hospital is not a crime in California), and mental patient extradition is barred by the one-year statute of limitations in sec. 51.84.2
The question before this court on review is one of statutory interpretation of the word “flight” in sec. 51.81, Stats.3 The issue is whether petitioner’s extra*378dition is barred by the statute of limitations in sec. 51.84, which provides that mental patient extradition proceedings must be begun within one year after the patient’s departure from the jurisdiction of the court in which proceedings are pending, or departure from the state where an individual was under detention as a person of “unsound mind.” The petitioner contends that his “flight” must be calculated as of July 28, 1979 (the date the California hospital noticed his absence and the date the petitioner testified he departed from the jurisdiction of the court), or August 2, 1979 (the date the Sacramento county superior court issued a bench warrant for his apprehension which indicated he was no longer under its jurisdiction). Thus petitioner argues that the one-year statute of limitations expired, at the latest, on August 2, 1980. Governor Dreyfus’s warrant for petitioner’s arrest for extradition was signed February 2, 1981 — six months after the statute of limitations would have run under the petitioner’s reasoning.
The trial court concluded that the word “flight” in sec. 51.81, Stats., meant the date the petitioner was discovered in Wisconsin, and consequently, California’s demand for extradition and Governor Dreyfus’s warrant for petitioner’s arrest for extradition were timely be*379cause the statute of limitations did not begin to run until April 8, 1980, the date Waukesha authorities contacted California authorities informing them of petitioner’s presence in the state. In the alternative, the trial court held that the issuance of the California bench warrant constituted commencement of the extradition proceedings. We agree with the trial court that the word “flight” in sec. 51.81 references a period of time from departure until the date of discovery of an escaped mental patient in a subsequent state. The statute of limitations, therefore, had not run on petitioner’s extradition. We do not reach the trial court’s alternative construction of “flight” commencing with the issuance of the California bench warrant.
Any analysis of statutory construction must begin with the language of the statute itself. Dawson Chemical Co. v. Rohm & Haas Co., 448 U.S. 176, 187 (1980) ; Reiter v. Sonotone Corp., 442 U.S. 830, 337 (1979) ; State ex rel. E.R. v. Flynn, 88 Wis. 2d 37, 42, 276 N.W.2d 313 (1979). Sec. 51.84, Stats., creates a one-year statute of limitations for the return of fugitive mental patients and specifically states: “Any proceedings under this chapter shall be begun within one year after the flight.” The term “flight” is defined in sec. 51.81, Wisconsin’s extradition statute which is this state’s enactment of the Uniform Act for the Return of Persons of Unsound Mind. “Flight” is construed to mean either (1) a voluntary or involuntary departure from the jurisdiction of the court during an ongoing proceeding, or (2) any departure from the state where a person demanded was under legal detention as being of “unsound mind.” Both parties agree that petitioner fits within the second definition, or category, of flight.4
*380Petitioner urges us to adopt a plain meaning interpretation of the statute of limitations in secs. 51.84 and 51.81, Stats.: Any extradition proceeding is to commence within one year of the absconder’s departure from the committing state. Respondent argues that the only reasonable construction of the statute is to construe flight as the date of discovery by the committing state of the patient’s presence in another state. In other words, flight refers to a span of time and distance over which the fugitive travels after leaving the mental institution until flight is ended by discovery.
At the outset of our analysis we are reminded: “Simply because the question presented is entirely one of statutory construction does not mean that the question necessarily admits of an easy answer.” Weinberger v. Rossi, - U.S. -, 102 S. Ct. 1510, 1513 (1982). We note that sec. 51.81, Stats., was originally created in 1919, and drafting records do not exist for the bill. Consequently, there is no legislative history available to guide us in our interpretation of this statute.
In construing any statute, our principal aim is to achieve a reasonable construction which will effectuate the statute’s purpose. See Jankowski v. Milwaukee County, 104 Wis. 2d 431, 436-37, 312 N.W.2d 45 (1981) ; Schwartz v. ILHR Dept., 72 Wis. 2d 217, 222, 240 N.W.2d 173 (1976) ; Pfingsten v. Pfingsten, 164 Wis. 308, 313, 159 N.W. 921 (1916). See also Holy Trinity Church v. United States, 143 U.S. 457, 459-60 (1892). We note that the overriding purpose of Chapter 51, Stats., is *381the treatment of persons suffering from mental illness. The purpose of secs. 51.81-51.85 is clearly the return of those in need of treatment to the place of original commitment where they were receiving such treatment. Thus we will construe these sections with this purpose in mind.
The departure referred to in sec. 51.81, Stats., can only be established with certainty when the committee is discovered in an asylum state. Sections 51.81-51.85 clearly recognize the legitimate interest of the committing state as being superior to that of the asylum state. Harmonizing the statutory interest in the treatment of the mentally ill and the statutory right of the committing state to claim the committee to implement its determination that treatment is needed clearly dictates the conclusion we reach.
Respondent convincingly argues that to construe the statute, of limitations in sec. 51.84, Stats., as running from the date of an absconder’s departure from the committing state would deny some fugitives the treatment they need. If an escaped patient were successful in eluding capture for a year, under such a construction, that person would no longer be subject to the treatment needed. This may encourage a patient who has resisted commitment and needs treatment to abscond and hide for a year. Departure time may be difficult to measure if a patient leaves but returns to the committing state only to subsequently depart again. . A very real difficulty, as we perceive this issue, is that, if flight is measured as of the date of departure from the demanding state, a court is frequently forced to rely solely upon the escaped committee’s testimony which may be designed to comport with a running of the statute of limitations or be unreliable because of the committee’s lack of mental competence. For example, in the instant case the only evidence of the date of petitioner’s departure from California is the petitioner’s testimony.
*382Respondent argues that defining flight as a period of time ending in discovery yields a very reasonable result which promotes the purpose of Chapter 51, Stats. The one-year limit forces the demanding state, upon discovery of the absconder in the asylum state, to review the ongoing inquiry and make a determination whether the absconder’s mental condition merits its determination that he is no longer in need of treatment and may be released from commitment. If the demanding state makes no demand within one year of the absconder’s discovery, either because it determines the absconder is no longer a societal threat or because the asylum state has sufficient control over the absconder or it takes no action, then the absconder is protected from extradition by the statute of limitations. This accomplishes the overriding purpose of Chapter 51: Treatment of persons adjudicated to be mentally ill.
Both petitioner and respondent cite to numerous dictionary definitions of the word “flight.” However, we do not find these definitions instructive in this case. There is also a dearth of case precedent in other jurisdictions dealing with this issue. Petitioner cites heavy reliance upon In re Chaffee, 211 Tenn. 88, 362 S.W.2d 467 (1962), for the proposition that a one-year statute of limitations in a uniform law is to be construed strictly in favor of the mental patient. See also Forgan v. Smedal, 203 Wis. 564, 570, 234 N.W. 896 (1931) (courts should construe uniform acts to the end that uniformity may result). We find that In re Chaffee, which did not deal with an escape, is distinguishable from the controversy before us (the mental patient in Chaffee had been released from a state institution, had established residency in a different state, and then petitioned the first state for a determination of sanity).
In interpreting statutes of limitations, petitioner analogizes the statute of limitations in sec. 51.84, Stats., to *383the statutes of limitations in the areas of tort and malpractice law to support his contention that the date of departure tolls the statute. We conclude, however, that different policy considerations are present in the case of extradition of mental patients and, therefore, such analogy is not warranted.
Petitioner makes the interesting argument that the practical problems with defining the date of flight as the date of departure are no greater than defining flight as the date of discovery. We find this argument unpersuasive because in the first instance the date of departure is usually known only to the committee. The date of discovery and the subsequent communication to the demanding state are usually a matter of public record.
While the legislature could have spoken with greater clarity, sound principles of statutory construction resolve our inquiry. While flight begins on the date of a patient’s departure from the committing state, it continues until the patient is discovered in the asylum state at which point flight ends, and the one-year statute of limitations is computed from that date. Accord Commonwealth v. Fusci, 153 Pa. Super. 617, 621, 35 A.2d 93, 95 (1943) (“Flight consists not only in the act of leaving the jurisdiction; it also comprehends continued concealment to avoid arrest and prosecution”) ; Commonwealth v. Myers, 131 Pa. Super. 258, 264-65, 200 A. 143, 146 (1938) (flight includes “ ‘the evading of the course of justice by voluntarily withdrawing oneself in order to avoid arrest or detention’ ”). We conclude that the only reasonable interpretation of the word flight is that it refers to the date the committing state discovers the presence of the absconder in the asylum state. Any other interpretation would encourage mental patients to abscond and hide for a year in order to gain their freedom from necessary confinement and needed treatment. Such *384a result would be clearly contrary to Chapter 51, Stats., which recognizes society’s interest in detaining mentally ill people in order to protect the public and afford such people appropriate treatment to restore their mental health.
By the Court. — The judgment and order of the circuit court are affirmed.
The issues certified by the court of appeals are: “(1) Are secs. 51.81-85, Stats., supplemental (and therefore to be read into) the Interstate Compact on Mental Health? (2) May a state which is not a member of the compact use those statutes to extradite an escaped patient from Wisconsin? (3) If not, what provisions, if any, may be used? (4) What constitutes ‘flight’ for purposes of the time limitation set forth in sec. 51.84, Stats.?”
The parties agree that secs. 51.81-51.85, Stats., are independent pieces of legislation from the Interstate Compact on Mental Health. The uniform act referred to in sec. 51.85 is the Uniform Act for the Extradition of Persons of Unsound Mind.
Unlike the Interstate Compact on Mental Health which limits its applicability to party states, the extradition provisions of secs. 51.81-51.85, Stats., contain no clause limiting the extradition of escaped mental patients to states which have enacted the uniform act. All parties agree that California may apply for extradition under secs. 51.81-51.85 as long as they comply with the statutory procedures. Accordingly, the first three issues certified by the court of appeals will not be addressed within this opinion.
Sec. 51.84, Stats., provides:
“51.84 Limitation of time to commence proceeding. Any proceedings under this chapter shall be begun within one year after the flight referred to in ss. 51.81 to 51.85.”
Sec. 51.81, Stats., provides:
“51.81 Definitions. The terms ‘flight’ and ‘fled’ as used in ss. 51.81 to 51.85 shall be construed to mean any voluntary or involuntary departure from the jurisdiction of the court where the *378proceedings hereinafter mentioned may have been instituted and are still pending with the effect of avoiding, impeding or delaying the action of the court in which such proceedings may have been instituted or be pending, or any such departure from the state where the person demanded then was, if he then was under detention by law as a person of unsound mind and subject to detention. The word ‘state’ wherever used in ss. 51.81 to 51.85 shall include states, territories, districts and insular and other possessions of the United States. As applied to a request to return any person within the purview of ss. 51.81 to 51.85 to or from the District of Columbia, the words, ‘executive authority,’ ‘governor’ and ‘chief magistrate,’ respectively, shall include a justice of the supreme court of the District of Columbia and other authority.”
Defense counsel argued petitioner also falls within the first category of flight as petitioner’s California commitment consti*380tuted close court supervision which is an ongoing proceeding. The assistant district attorney argued the first definition of flight was inapplicable because once an order of commitment is entered there is no ongoing proceeding. Because we agree with the parties that petitioner clearly falls within the second definition of flight, we need not examine these arguments.