NASHUA — A Hillsborough County Superior Court jury, after a three-day trial, found a Dracut, Mass., man to be innocent of the first-degree assault in August 2017 of his then-girlfriend in Nashua, who suffered severe injuries.

The unanimous jury verdict meant that after 15 months of detention and a $100,000 cash bail demand his family could not meet, Cyrinus Franklin “Frank” Morris, 49, walked out of prison a free man Friday afternoon.

His lead lawyer, Theodore “Ted” Lothstein of the law firm Lothstein Guerriero PLLC in Concord, said these criminal trials always have built-in risks of defeat but this was a big victory given his client initially faced an attempted murder charge that carried up to life in prison.

“I am a worst-case scenario person. I never think I am going to win. There is evidence against a person; they are in trouble and they are in jeopardy,” Lothstein said during a telephone interview after the verdict came in following two hours of deliberation.

At the outset of the trial, prosecutors had dropped the attempted murder charge.

Morris had still faced an enhanced first-degree assault charge alleging “extreme cruelty and depravity” that would have carried a 10- to 30-year prison sentence, had he been convicted.

All told, Morris faced three felony charges and Superior Court Judge Jacalyn Colburn in instructions had advised the jury they could alternatively choose to find Morris guilty of three lesser offenses.

He was acquitted on all pending charges.

Senior Assistant County Attorney Kent Smith prosecuted the case. He could not be reached for comment at his office after the verdict, which the jury returned just before 11 a.m. Friday.

Morris’ former girlfriend, Christina Cozzone, 43, of Nashua, testified at trial that Morris had attacked her.

Cozzone needed weeks of hospital care after suffering a head injury that required doctors at Massachusetts General Hospital to install a drain in her skull to relieve pressure on her brain, according to court documents.

Morris did not take the stand in his own defense.

Morris had told police the pair had been drinking on the day of the attack and that Cozzone could be clumsy.

He said he found her in her apartment face down, unconscious, and he called 911.

“I really do think the police investigation didn’t reveal any evidence inconsistent with what he was saying all along,” Lothstein said.

Lothstein said the jury was unusually well prepared and focused on the task at hand.

“Most of us who hang out in court, we have seen jurors fall asleep, nodding off, looking bored. Most juries have one or two people who are not engaged; they mirror society,” Lothstein said.

“That was not this jury. Everybody was riveted to everything they heard, both sides were really paid attention to, this jury was not missing a thing.”

Lothstein introduced at trial that his client fully cooperated with the investigation, which included giving police the keys to the apartment, providing written permission to search all contents of his phone and submitting to hours of interrogation without a lawyer