I am pleased to join the judgment and opinion of the court. I write separately, however, to emphasize a point not addressed in Judge Ruiz’ opinion, namely, that Tyler’s right to present exculpatory evidence at his preventive detention hearing exists independently of the question of dangerousness1 and is not restricted in any way to that issue.
I.
The general procedures applicable to preventive detention hearings are set forth in D.C.Code § 23~1322(d) (1996).2 Subsection (3) of that provision states that the defendant shall be afforded an opportunity to testify. Subsection (4) provides, inter alia, that he shall be afforded an opportunity to present witnesses. There is no restriction in Section 23 — 1322(d) with respect to the issues as to which the defendant may testify or present witnesses. I therefore discern no statutory basis for the government’s position that any presentation of exculpatory evidence must be confined to the issue of dangerousness and may not go to the question of the defendant’s guilt or innocence of the charged offense.
To construe the statute as the government does seems to me to fly in the face of common sense. No matter how dangerous the defendant may be, and no matter how many previous crimes he may have committed, surely he cannot be preventively detained if the most important evidence of all — proof that he probably “did it”- — collapses. Suppose that Tyler could establish beyond peradventure that he was in Papua or Peru or prison when the crime was committed. It is inconceivable to me that such exculpatory evidence may be excluded. Yet the trial judge, in ordering Tyler’s detention, stated that she “prefer[red] ... not to know anything about the case,” and her ruling thus excluded evidence relevant to the question whether preventive detention was warranted.
In my opinion, the defendant’s right to present evidence that he did not commit the charged crime is so fundamental that there should be no need invoke august canons of statutory construction. Since others appar*279ently disagree, however, I note Chief Justice Rehnquist’s apt reminder that “[i]n our society, liberty is the norm, and detention prior to trial is the carefully limited exception.” United States v. Salerno, 481 U.S. 739, 755, 107 S.Ct. 2095, 2105, 95 L.Ed.2d 697 (1987); see also Covington v. United States, 698 A.2d 1033, 1037 (D.C.1997) (quoting Salerno). Preventive detention statutes restrict the liberty of the citizen, and they must be strictly construed to ensure that defendants are not detained without bond “unless the lawmaker has clearly said that they should [be].” United States v. Bass, 404 U.S. 336, 348, 92 S.Ct. 515, 523, 30 L.Ed.2d 488 (1971) (citations omitted). Section 23-1322(d) contains no provision clearly precluding the defendant from presenting the type of exculpatory evidence that the trial judge excluded, and the government’s position is contrary to the principle enunciated in Bass.
Moreover, statutes should be construed, if reasonably possible, to avoid any doubt as to their constitutionality. Umana v. Swidler & Berlin, Chartered, 669 A.2d 717, 723-24 (D.C. 1995). “[A]s between two possible interpretations of a statute, by one of which it would be unconstitutional and by the other valid, our plain duty is to adopt that one which will save the act. Even to avoid a serious doubt the rule is the same.” NLRB v. Jones & Laughlin Corp., 301 U.S. 1, 30, 57 S.Ct. 615, 621, 81 L.Ed. 893 (1937) (citations omitted). An interpretation of Section 23-1322(d)(3) and (4) which would restrict the defendant from presenting evidence that he did not commit the offense would, at the very least, raise serious constitutional questions, and we should therefore reject such a construction.
The government contends that, because the grand jury found probable cause that Tyler committed the charged offense, the preventive detention hearing should not concern itself with evidence that the defendant did not “do it.” Like the court, I disagree. Tyler had no opportunity to be heard before the grand jury. The finding of probable cause was made following a non-adversarial proceeding in which the defendant could not present exculpatory evidence. Such a determination cannot control the disposition of an adversarial hearing in which the defendant has a right to testify and call witnesses and in which his fundamental liberty interests are directly at stake.
If a defendant who did not commit the crime is preventively detained, a subsequent finding that he is innocent cannot give him back the time spent in detention. He must therefore be given the opportunity to show his innocence before a detention order is entered.
II.
Judge King and the judges who join him make a persuasive case for the proposition that the precise situation here presented does not arise frequently. I do not think that it follows from that showing, however, that the appeal should be dismissed as moot. In my view, the position taken by the government and adopted by the trial judge has implications that go well beyond these particular facts. The trial judge’s order in this case, affirmed by a divided panel of this court, was contrary to the basic principle that no defendant may be preventively detained without first being given the opportunity to try to show that he did not commit the crime with which he has been charged. If we were to dismiss the appeal as moot, the government’s position — a fallacious one, in my view — would remain viable, and the government could invoke it again in the future.
In most circumstances, we should decide no more than we have to decide. As Judge Ruiz points out, however, preventive detention cases such as this one necessarily move fast, and they tend to evade review. An appellate court can rarely decide a preventive detention issue while the controversy is still live. I therefore agree with Judge Ruiz that, in the exercise of our discretion, we should decide the merits of the case rather than dismissing Tyler’s appeal.
I am reinforced in that view by the fact that we voted some time ago to go en banc, and that we have now proceeded to consider the contentions of the parties on the merits (as well as with respect to mootness). Both sides are represented by excellent counsel. Notwithstanding Tyler’s guilty plea, the Public Defender Service has every incentive to argue vigorously on behalf of his initial position. The government has fought hard as well.
*280The argument that we should not decide this case on the merits was in its most persuasive posture prior to our vote on the petition for rehearing en banc. Even at that time, a majority of the court voted to grant the petition. Now that the case has proceeded to this point, I think it would be incongruous to step backwards and decline to rule on the substantive issue. I agree with Chief Justice Rehnquist that “once this court has undertaken a consideration of a case, an exception to [the mootness] principle is warranted.” Honig v. Doe, 484 U.S. 305, 332, 108 S.Ct. 592, 609, 98 L.Ed.2d 686 (1988) (concurring opinion); accord, In re Melton, 597 A.2d 892, 908 n. 32 (D.C.1991) (en banc). This is especially true where, as here, the court has had the benefit of a first-rate adversarial presentation.
If we carry the doctrine of mootness too far in this particular area, then effective review of orders curtailing fundamental liberty interests will be irretrievably impaired. I therefore join the court' in rejecting the government’s position that we should dismiss the appeal as moot.
. In using the word dangerousness, I include both danger to the community and danger that the defendant may not appear in court as required.
. Section 23-1322(e) sets forth the considerations applicable to the judge’s determination whether there are conditions, short of preventive detention, that will reasonably assure the safety of the community and the defendant’s appearance in court. I agree entirely with Judge Ruiz' discussion of this provision.