ORDER
HARRIS L HARTZ, Circuit Judge.Appellee’s petition for rehearing is denied.
The petition for rehearing en banc was transmitted to all of the judges of the court who are in regular active service. As no member of the panel and no judge in regular active service on the court requested that the court be polled, that petition is also denied.
The order and judgment issued February 6, 2014, — Fed.Appx. -, 2014 WL 464222, is withdrawn, and the attached *464amended order and judgment is issued nunc pro tunc February 6, 2014.
ORDER AND JUDGMENT*
Plaintiff David Garcia appeals the district court’s order granting summary judgment to Bernalillo County Sheriffs Officer R. Garcia and his supervisor, Sergeant Escalante, on Plaintiffs civil-rights claims under 42 U.S.C. § 1983. Plaintiff asserted claims that his Fourth Amendment rights were violated by an unreasonable search and arrest and by his prosecution without probable cause, and that his First Amendment rights were violated when he was arrested in retaliation for protected speech. The magistrate judge, sitting by consent of the parties, see 28 U.S.C. § 636(c), granted Defendants’ motion for summary judgment, ruling that, based on the undisputed facts, Defendants were entitled to qualified immunity on all claims because there had been no constitutional violation. We have jurisdiction under 28 U.S.C. § 1291. We hold that there is a genuine dispute of material fact regarding whether Defendants had probable cause to arrest and charge Plaintiff, and therefore reverse on the Fourth Amendment claims. We affirm on the First Amendment claims, however, because Plaintiff presented no evidence of a retaliatory motive. Plaintiff does not challenge on appeal the adverse ruling on his unlawful-search claim.
BaCkground
In March 2009, Plaintiff entered a New Mexico state courthouse with a metal vial attached to his key chain. Officer Garcia, working security, opened the vial and found a number of pills, including hydroco-done pills. The parties do not dispute that hydrocodone is a controlled substance, or that Plaintiffs mother, who was with Plaintiff, left the courthouse with another officer, Officer McCauley, and returned with prescription records. The parties do dispute, however, whether any of the prescriptions was for hydrocodone. Officer Garcia arrested Plaintiff for possessing a controlled substance without a valid prescription, see N.M. Stat. Ann. § 30-31-23(A) (“It is unlawful for a person intentionally to possess a controlled substance unless the substance was obtained pursuant to a valid prescription .... ”), and later filed a criminal complaint. The charge was eventually dismissed.
Plaintiffs complaint alleged that Officer Garcia lacked probable cause to arrest him because at the time of his arrest he and his mother provided Officer Garcia with a valid prescription for the hydrocodone. Defendants moved for summary judgment based on Officer Garcia’s affidavit stating that Plaintiff did not have a valid prescription for hydrocodone with him at the time of his arrest. In response, Plaintiff relied upon his deposition testimony and documents showing that he had filled hydroco-done prescriptions on three occasions before his arrest (in October 2007, January 2008, and February 2008) and twice after his arrest (in April and September 2009). We quote the relevant deposition testimony. When asked if he had provided the January 2008 prescription to Officer Garcia, Plaintiff answered:
This exact label? Or — I have a label that I did provide that looks very similar. I did not provide a bottle. I did *465provide a label, a label that had this exact same information on it. Maybe not the exact date, but, you know, the date proves — actually, it must have been — well, no, it wasn’t from this date. And it was from this date; and then even after this incident, I was still prescribed hydrocodone.
R. Doc. 41-5 at 5. Later in the deposition he was shown Exhibit M (which consisted of six prescriptions, none for hydrocodone, that had been tagged into evidence at his arrest) and was asked about the absence of a hydrocodone prescription:
Q. ... After you got arrested, your mom left the courthouse to go obtain a copy of your prescriptions. Is that correct?
A. Followed by Officer McCauley, correct.
Q. Okay. And she provided, then, some documentation to law enforcement about your prescriptions, the pills that were contained in the vial.
A. She brought back — yes, she did, in fact, bring back this information, what you’re presenting in Exhibit M.
Q. Okay.
A. But it’s not complete.
Q. You’re saying she brought back an additional prescription that’s not contained in Exhibit M?
A. Let me — Let me go ahead and go through them. My attorney did. Okay. Correct. Hydrocodone was provided.
Q. So you’re saying a prescription for hydrocodone was provided.
A. That is correct.
A. ... Well, I’m telling you that hy-drocodone was, in fact, provided.
Q. You’re saying a prescription for hy-drocodone was provided.
A. Correct.
R. Doc. 41-5 at 6 (emphasis added).
The magistrate judge ruled that Plaintiff failed to submit any admissible evidence that he or his mother provided a valid prescription for hydrocodone to Officer Garcia. He concluded that it was “undisputed” that Officer Garcia “discovered that [Plaintiff] possessed a controlled substance without a valid prescription for the medication,” and therefore he had probable cause to arrest Plaintiff. R. Doe. 68 at 15. He also ruled that Plaintiff had presented no evidence that his arrest was in retaliation for his exercise of First Amendment rights. Accordingly, the magistrate judge granted summary judgment to Defendants. Plaintiff filed a Motion to Alter or Amend a Judgment under Fed.R.Civ.P. 59(e), but it was denied.
Analysis
“Qualified immunity shields government officials from liability for civil damages insofar as their conduct does not violate clearly established statutory or constitutional rights of which a reasonable person would have known.” See Romero v. Story, 672 F.3d 880, 882 (10th Cir.2012) (internal quotation marks omitted). “When a [§ 1988] defendant asserts qualified immunity at summary judgment, the burden shifts to the plaintiff to show that: (1) the defendant violated a constitutional right and (2) the constitutional right was clearly established.” Courtney v. Okla. ex. rel, Dep’t of Pub. Safety, 722 F.3d 1216, 1222 (10th Cir.2013) (internal quotation marks omitted). The magistrate judge based his summary judgment on Plaintiffs failure to make the first showing, so he did not need to address whether the applicable law was clearly established. We review the magistrate judge’s grant of summary judgment de novo. See id.
*466“[A]n officer may make a warrantless arrest if there is probable cause to believe a criminal offense has been or is being committed.” Id. at 1225. “Whether probable cause exists depends upon the reasonable conclusion to be drawn from the facts known to the arresting officer at the time of the arrest.” Id. (internal quotation marks omitted). On appeal Plaintiff contends that he presented evidence sufficient to create a genuine issue of material fact on whether the prescriptions provided to Officer Garcia included one for hydroco-done, and thus whether there was probable cause to arrest him.1
It is unclear why the magistrate judge decided that Plaintiff had presented no admissible evidence that his mother had provided the officers a hydrocodone prescription. The magistrate judge wrote: “There is no affidavit statement from Plaintiffs motion in support of [his] assertions, and a party may not rely on hearsay.” R. Doc. 68 at 8. But Plaintiffs deposition testimony was not hearsay. It was based on his personal knowledge, just as much as Officer Garcia’s contrary affidavit was based on his personal knowledge of what Plaintiffs mother showed the officers. There is no reason to believe that Plaintiff could not see the documents provided by his mother to the officers. A sworn statement from his mother was not required. At summary judgment, “evidence of the non-movant is to be believed, and all justifiable inferences are to be drawn in his favor.” Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986). Corroboration is unnecessary. Further, “if ‘reasonable persons could differ as to whether the witness had an adequate opportunity to observe, the witness’s testimony is admissible.” Strong v. Valdez Fine Foods, 724 F.3d 1042, 1045 (9th Cir.2013) (quoting 1 McCormick on Evidence § 10 (Kenneth S. Broun, ed., 7th ed. rev. 2013)).
Defendants argue that even if Plaintiffs mother had given Officer Garcia the January or February 2008 prescriptions for hydrocodone, they would not have been valid prescriptions. Defendants rely on 21 U.S.C. § 829(b), which states that prescriptions for a controlled drug such as hydrocodone “may not be filled or refilled more than six months after the date thereof.” But Plaintiff was not trying to fill a prescription. He was simply showing that his drugs had been obtained with a prescription. The statute cited by Defendants does not require the patient to consume all the medication within six months of the *467prescription date. In our view, Plaintiff submitted sufficient evidence to support his claim that his arrest was without probable cause.
Defendants also argue that they are entitled to qualified immunity because the applicable law was not clearly established at the time of Plaintiffs arrest and prosecution. We leave that question for the district court in the first instance. We further note that because there are disputed facts about what prescriptions were presented by Plaintiffs mother, Plaintiff is not entitled to summary judgment on the validity of his arrest and prosecution.
Finally, we hold that the magistrate judge correctly ruled that Plaintiff failed to produce evidence that his arrest was in retaliation for exercising his First Amendment rights. He asserts in his pleadings that the officers were retaliating against him because he had said that he had come to the courthouse to file a lawsuit against other law-enforcement officers. But the deposition testimony on which he relies says only that he told the officers that he had come to file a lawsuit — with no mention of whom he was suing.
Plaintiffs motion to proceed in forma pauperis is granted. Defendants’ motion for sanctions and Plaintiffs motion to expand and modify the record are denied. We affirm the judgment below on Plaintiffs First Amendment claims but reverse and remand for further proceedings on his Fourth Amendment claims. The district court may reconsider whether to grant further discovery.
After examining the briefs and appellate record, this panel has determined unanimously that oral argument would not materially assist the determination of this appeal. See Fed. R.App. P. 34(a)(2); 10th Cir. R. 34.1(G). The case is therefore ordered submitted without oral argument. This order and judgment is not binding precedent, except under the doctrines of law of the case, res judicata, and collateral estoppel. It may be cited, however, for its persuasive value consistent with Fed. R.App. P. 32.1 and 10th Cir. R. 32.1.
. In contravention of Fed. R.App. P. 30(a)(1)(B) and (C), and 10th Cir. R. 30.1(A)(1) and 10.3(D)(2), Plaintiff's Appendix fails to include any of the orders being appealed or many of the briefs filed in the district court related to the issues he raises on appeal, including his response to the motion for summary judgment, Defendants’ reply thereto, Defendants’ motion for bill of costs, or Plaintiff's response thereto. Further, in contravention of Fed. R.App. P. 30(d), Plaintiff’s Appendix failed to present the record in the Appendix chronologically. As examples, the transcript of Plaintiff’s deposition found in the Record at Doc. 41-5, was placed in the Appendix between R. Docs. 37 and 38, see Aplt. App. at 95-106, and R. Doc. 41 was placed in the Appendix before Doc. 39, see Aplt. App. at 114, 134. Finally, the end of the Appendix is not numbered consecutively. See Aplt. App. at 224-38.
Counsel for Defendants supplemented the record, and we accessed other missing pleadings through the district court’s docket. But we admonish counsel for Plaintiff that "[i]t is not this court’s burden to hunt down the pertinent materials. Rather, it is Plaintiff’s responsibility as the appellant to provide us with a proper record on appeal.” Rios v. Bigler, 67 F.3d 1543, 1553 (10th Cir.1995). "Our procedural rules should not be considered empty gestures, as we have repeatedly enforced them.” Burnett v. Sw. Bell Tel., L.P., 555 F.3d 906, 910 (10th Cir.2009) (brackets and internal quotation marks omitted).