Jeffery Trevino's defense had a tough challenge in overcoming the large amount of forensic and video surveillance evidence stacked against him, as well as a motive that tapped into primal human instincts, said local attorneys who reflected on the recent trial.

Trevino, 39, was convicted Wednesday of second-degree murder without intent, meaning jurors believed that he killed his wife, Kira Steger, during an assault but that he didn't intend to kill her. The jury of four women and eight men acquitted him of second-degree murder with intent after 17 hours of deliberation and eight days of testimony that revealed his wife was cheating on him.

"I think a lot of people can understand how that happened," defense attorney J. Anthony Torres said of murder without intent. "Everything leading up to her death suggested he didn't have any plans to hurt her that night. They went to dinner. He was hoping they could fix their marriage, and all of a sudden, in a very short period of time, she's gone, which suggests to most reasonable people … there might have been a lot of passion involved in what happened."

Trevino and Steger, 30, had a date night at the Mall of America on Feb. 21 to talk about the future of their marriage, which was on the verge of divorce. The two had dinner at Crave, went bowling and watched a movie upon returning to their home in the 500 block of Iowa Avenue E. in St. Paul.

Throughout the evening, Steger texted a co-worker she was having an affair with. Assistant Ramsey County Attorneys Richard Dusterhoft and Andrew Johnson told jurors that Trevino killed Steger within two hours of the last text she sent the other man at 11:44 p.m. Trevino reported Steger missing to police on Feb. 24 and was charged in her death a few days later. A barge mechanic found her body on May 8 in the Mississippi River.

Trevino's attorney, John Conard, raised the idea that Steger's marijuana use could have factored into her death and that the forensic evidence was misleading. He also implied that Steger's grandfather could have planted a bloody pillow prosecutors believe was used to smother her.

Conard had a difficult case, but implicating the grandfather probably just "turned off" the jury, said Joseph Daly, emeritus professor at the Hamline University School of Law.

"That was a big mistake by the defense," said Daly, a former prosecutor and defense attorney. "One of the things you do is you pick the most reasonable theory in your case and you press forward on that theory."

Daly thought Conard's strongest theory was one that suggested someone involved in marijuana could have killed Steger. But Torres and defense attorney Gary Wolf said public perception has changed so much that few associate danger with recreational users.

"If she was selling kilos of marijuana, that'd be different," Torres said.

Wolf said introducing multiple theories can, at the very least, result in a hung jury.

But the prosecution's evidence was overwhelming in this case, said Torres and Wolf. Both said they didn't think an acquittal on all counts was possible.

"I think it was open-and-shut for a conviction," Wolf said. "The case had all the earmarks of a heat-of-the-passion assault."

Daly said a tight timeline prosecutors presented using surveillance video was key in the case, although they dropped the ball by not investigating where Steger received her marijuana, opening the door for Conard's theory.

Wolf praised Conard for raising enough doubt to get the acquittal on intentional murder. Both intentional and unintentional second-degree murder carry a maximum sentence of 40 years in prison, but unintentional murder will likely result in much less time. Conard said Wednesday that Trevino is probably looking at closer to 20 years in prison.

"The defense, I think, scored a victory," Wolf said. "It's a huge difference for the defendant."

Conard also had the option of having the court ask jurors at the end of testimony to consider a manslaughter conviction instead, a lesser count that would result in a prison term in the single digits, Wolf said. But that requires the defendant or another witness testifying that the defendant killed the victim in the heat of passion.

"They didn't do that because they wanted to be acquitted," Wolf said. "I'm sure that was the client's decision."

Wolf used the manslaughter strategy in 2006 when he represented a man charged in Ramsey County with first-degree murder and second-degree murder. The jury acquitted Wolf's client on all counts, including first-degree manslaughter, even though the man testified that he fatally shot at his brother-in-law 21 times with an assault rifle.

Wolf said his client came off as sympathetic, while the victim's family and prosecutors' witnesses "blew up" on the witness stand and made a bad impression on jurors. Steger's likability and her family's all-American appeal were "a huge mountain" for Conard and Trevino to overcome, he said.

Trevino didn't testify, which is not unusual.

Daly said Trevino simply didn't look likable enough to win anyone over, regardless of what he might have said.

"This was civilized warfare," Daly said. "You go into a trial and your intention is to win, not to lose."

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib