A federal judge overseeing an excessive force lawsuit against Bozeman police has found that authorities intentionally erased a missing audio recording of the incident.

And while U.S. District Judge Richard Anderson found the recording central to figuring out what happened during the incident more than five years ago, he didn’t immediately find the Bozeman Police Department liable for the injuries sustained by Soheil Jesse Verdi.

In his ruling issued last month, however, Anderson found the missing audio relevant, intentionally erased and “extremely suspicious.”

Verdi filed the lawsuit in 2009 against the police department, the city of Bozeman, Sgt. Greg Megargel, officer Marek Ziegler, former police Chief Mark Tymrak and former Deputy Chief Martin Kent.

The suit charges the defendants with excessive use of force, assault and battery, intentional infliction of emotional distress, negligence, false imprisonment, evidence spoliation and conspiracy. Verdi is seeking unspecified damages. A trial date has not been set.

According to the lawsuit:

On Aug. 12, 2007, a friend of Verdi’s called Bozeman police requesting a welfare check on Verdi. Officers Megargel and Ziegler responded to Verdi’s home.

Verdi was naked, intoxicated and “stumbling around” when he answered the door. Officers claimed when Verdi “suddenly attacked,” Ziegler tased him in the back.

Verdi fell face down onto his deck outside of the apartment, hitting his head and causing injuries to his skull. Verdi’s attorneys claim he has had three brain surgeries to remove excessive blood on his brain and to help with headaches.

In August, Verdi’s attorneys asked the court to find the police department liable and to award Verdi damages based on a missing audio segment recorded on the day of the tasing.

Police provided five recordings from Ziegler’s microphone that were numbered 168, 169, 171, 172 and 173. There was no recording numbered 170.

In a November court hearing, Ziegler testified he would turn his body recorder on and off as he saw fit. He said nothing happened during the time period of the missing segment, which he thought was about three or four minutes.

During that time, he said both officers probably told medical responders what had happened.

At the police station after the incident, Ziegler said he transferred the audio to a computer. He said he didn’t remember if the audio was missing at the time.

Ziegler said he normally deletes audio recordings at the scene of an incident if he decides they aren’t relevant.

In his ruling, the judge said all the defendants agreed the audio segment is missing, but they haven’t made any meaningful effort to figure out why.

If the audio existed, the judge said it would be favorable to Verdi’s claims of excessive force.

“Segment 170 is the best evidence regarding what transpired during the three to four minutes in question and is, therefore, relevant and material,” Anderson wrote.

However, he said the facts in the case are a “close call,” and he wouldn’t immediately rule against the police department. He did rule, though, that if the case proceeds to trial, he would instruct the jury that the missing audio “would be relevant and favorable to some or all of the plaintiff’s claims of excessive force. The instruction should explain that the law does not condone the intentional destruction of evidence by officers of the law.”

Verdi’s attorneys filed an objection this week to the judge’s ruling. They again asked the judge to rule in Verdi’s favor.

In the objection, Verdi’s attorneys also dispute Anderson’s interpretation of audio from the incident.

After the ambulance left with Verdi, Anderson wrote that Megargel is heard saying, “Now what the (expletive)?”

Verdi’s attorneys contend that Megargel said, “Now we’re (expletive).” They requested that Anderson clarify the transcription.

Whitney Bermes can be reached at wbermes@dailychronicle.com or 582-2648. Follow her on Twitter at @wabermes.