Defendant, Robert Cervantes, was convicted by a jury of second degree assault, third degree assault, obstructing a police officer, and resisting arrest. On appeal, he challenges the second degree assault conviction. We affirm.
The offenses committed here arose out of a family dispute between defendant and his estranged wife and an altercation between defendant and police officers who were summoned to the scene. Defendant was initially charged in an information with, inter alia, first degree assault of police officer Joseph Tymkowych by use of a deadly weapon, to wit, a St. Bernard dog. Following a preliminary hearing, the court found probable cause lacking as to this count, bound the charge over as second degree assault, and directed the prosecution to file an amended information. The prosecution’s motion to amend to charge second degree assault was granted on February 5, 1980, and the count was amended to charge defendant with violating § 18-3-203, C.R.S.1973 (1978 Repl.Vol. 8). No subsection was cited in the amended information, and it stated that defendant:
“with intent to prevent Joseph Tym-kowych, whom he knew and reasonably should have known to be a peace officer, did unlawfully, feloniously, and intentionally cause bodily injury to Joseph Tymkowych.”
At an in camera hearing held after the jury had been selected and sworn on the first day of trial, November 24, 1980, defendant moved to dismiss this count on the grounds that it failed to charge an offense in that it failed to allege a culpable mental state and did not provide proper notice of the actual charge against defendant. The court denied the motion noting .that although the written count did not “make sense,” the parties knew as a result of the preliminary hearing that the count was bound over as second degree assault, defendant should have made the motion prior to arraignment, and the information could be amended at that time because an amendment would be a matter of form. The court then asked the prosecution if it wanted to move to insert the words “from performing a lawful duty” (as modifying “with intent to prevent,” see § 18-3-203(l)(c), C.R.S.1973 (1978 Repl.Vol. 8)), the prosecution so moved, and the amendment was granted. Defendant later renewed the motion to dismiss this count, challenging the propriety of granting the amendment, and this motion also was denied.
Crim.P. 7(e) allows for an information to be amended as to form or substance at any time prior to trial, but restricts amendments after the commencement of trial to amendments as to form, and then only “if no additional or different offense is charged and if substantial rights of the defendant are not prejudiced.” On appeal, the People do not contest that the amendment to add the words “from performing a lawful duty” occurred after the trial began. Rather, the People argue, as the trial court found, that the amendment was one of form. Conversely, defendant argues that the amendment was one of substance and was therefore prohibited by Crim.P. 7(e). Under the unusual facts here, we hold that the amendment was properly granted.
A criminal information serves a variety of purposes. It serves to advise a defendant of the nature of the charges against him, enables him to prepare his defense, and enables him to plead the judgment in bar of any further prosecution for the same offense. See People v. Donachy, 196 Colo. 289, 586 P.2d 14 (1978). However, to be sufficient an information need not allege every element of an offense. See People v. Ingersoll, 181 Colo. 1, 506 P.2d 364 (1973).
Here, defendant was well aware following the preliminary hearing that the charge was bound over as second degree *405assault and that the prosecution was directed to file an amended information. Moreover, the February 5, 1980, motion to amend, to which the amended information was attached, stated that the prosecution sought to amend to allege second degree assault. Although the amended information was inartfully worded, there is no question that defendant knew he was being charged with second degree assault, and the language used in the amended information could only be construed as alleging a violation of § 18-3-203(l)(c), C.R.S.1973 (1978 Repl.Vol. 8). Accordingly, the information was sufficient for purposes of Crim.P. 7(c). See Petty v. People, 156 Colo. 549, 400 P.2d 666 (1965). Therefore, when the inartful information was brought to the court’s attention on November 24, 1980, and the prosecution moved to amend to add the missing words, the amendment was one of form and was properly allowed by the court. The amendment did not result in an additional or different charge against defendant, and defendant, having failed to request a continuance, has no basis for claiming prejudice or surprise. See Crim.P. 7(e); People v. Marion, 182 Colo. 435, 514 P.2d 327 (1973).
Moreover, we find the rationale of People v. Dickinson, 197 Colo. 338, 592 P.2d 807 (1979) apropos here. In that case, the information was originally amended in February 1980, but defendant waited until November 1980, after the jury had been selected and sworn, to challenge the information. Defendant failed to raise the challenge earlier - when any deficiency might easily have been cured by amendment. The court ruled defendant had waived his right to attack a defect in the information, stating: “Unless enforcement of procedural requirements is essential to shield substantive rights, litigation should be determined on the merits and not on the basis of technical rules.” People v. Dickinson, supra. See also People v. Hertz, 196 Colo. 259, 586 P.2d 5 (1978); Mora v. People, 172 Colo. 261, 472 P.2d 142 (1970).
Judgment affirmed.
KELLY, J., concurs. TURSI, J., dissents.