One of the Prince George’s County police officers caught on video beating an unarmed University of Maryland student during a raucous basketball postgame celebration in 2010 testified on Thursday that he saw the student punch another officer before he struck him “at least” seven times with a baton because the student would not drop an object in his hand.

That object, Officer James Harrison Jr. would later learn, was a cellphone. Video seems to show that the so-called punch was John McKenna raising his arm in a defensive position. But Harrison testified that from his perspective, McKenna had just assaulted a police officer and he needed to use his baton “in order to subdue him and bring him under control.”

“I absolutely feel it was necessary,” Harrison testified. “Absolutely.”

Harrison and another officer, Reginald Baker, are charged with second-degree assault and misconduct in office in connection with the now-infamous March 2010 beating of McKenna after the University of Maryland’s basketball victory over Duke. A judge threw out a more serious charge of first-degree assault on Wednesday, the third day of testimony in the officers’ trial in Prince George’s County Circuit Court.

Prosecutors have alleged that the pair went too far in striking McKenna repeatedly after they forced him to the ground.

In many ways, Harrison echoed the sentiments of Baker, who testified Wednesday.

Like Baker, Harrison said the crowd had sworn at police and thrown ice chunks and bottles at them.

He said McKenna’s “bizarre behavior” — coming at a police line despite orders to leave — worried him.

But Harrison went further than Baker, saying that he wondered whether McKenna was “on PCP,” which he knew from experience could give people “superhuman strength.”

He said he saw McKenna “take a strike at [Baker] with a clenched fist” — something Baker himself said he did not completely perceive.

And Harrison said that even after Baker knocked McKenna to the ground with a riot shield, he felt it necessary to club the student repeatedly — some of his strikes hit only pavement — so McKenna would drop an object in his clenched hand.

“I’m continuing to strike him, and I’m giving one command: ‘Drop it!’ ” Harrison testified, his booming voice filling the courtroom.

As they did with Baker, defense attorneys sought to bolster Harrison’s credibility by calling character witnesses and asking him about his work and family. Harrison, 48, testified that he is married with eight children, three of whom are in college. He said he had served in the Navy and Army Reserves.

Harrison acknowledged that he had not filled out a “use of force” report in connection with the incident and that he initially lied to an internal affairs investigator who asked in April 2010 if he was shown on the video.

Tearing up, Harrison said he did so because he had seen the police chief on local TV threatening to fire those involved in the incident, and he worried about his personal finances should that happen.

Harrison said his wife had recently lost her job and he was coping with the financial effects of police furloughs.

“It would definitely impact my house,” Harrison testified. “To go into that, it was difficult.”

The trial was delayed for several hours Thursday as attorneys huddled behind closed doors with Judge Beverly Woodard. Individuals familiar with the case, who spoke on the condition of anonymity because the trial was continuing, said that attorneys for both sides had learned that the judge’s ex-husband was a former Prince George’s police officer who had been convicted in an excessive-force case before he and the judge were married.

There was some discussion about whether that would constitute grounds for a mistrial, the sources said, but Woodard said she had been divorced from the man for at least five years and could be impartial.

Neither side moved for a mistrial, and the proceedings continued.

The trial is expected to shift to closing arguments Friday after testimony concludes.