TAMPA — In the hours after he killed his girlfriend and her two children, Edward Covington stabbed them repeatedly, mutilated their bodies and covered their modest mobile home in Lutz with their blood. Wearing nothing but underwear, he hid in a closet, burying himself under a mountain of children's toys and clothing so that only the top of his head was visible.That was as far as his effort to evade capture went, prosecutors said. Days later, when questioned by detectives, he confessed to everything.On Wednesday, the opening day of Covington's trial, prosecutors described his alleged crimes in nauseating detail, suggesting to jurors that the only fair response to one of the goriest murder cases in Hillsborough County history is the death penalty. On Mother's Day 2008, Covington had demanded his girlfriend, Lisa Freiberg, hand over her bank cards and car keys, prosecutor Sheri Maxim said. Freiberg promised that if he spared her life, she would get them for him. He killed her anyway, Maxim said.Later, he would tell detectives: "She did nothing but love me. And the kids loved me."Defense attorney Mike Peacock acknowledged the case was not a "whodunit." But he asked jurors to concentrate on whether Covington's actions sounded like the work of a calculating criminal."The person who did these acts was not sane," he said, briefly summarizing his client's long history of mental illness and a diagnosis of bipolar disorder at age 15. In court documents and previous hearings, public defenders have laid out their defense in greater detail. Covington had no intention of harming Freiberg or her two children, Zachary, 7, and Heather Savannah, 2, they contend. But when he lost his job as a prison guard with the Department of Corrections and the health insurance that came with it, he stopped taking his medications. Without the mood stabilizers, he fell into an uncontrollable bipolar rage, fueled by cocaine and alcohol abuse.On Wednesday, Peacock told jurors that his client was not guilty of premeditated murder. At most, the killings could be classified as second-degree murder, he said, committed without forethought.Covington, 43, was charged 6 1/2 years ago with animal abuse and three counts each of first-degree murder and abuse of a human body. In early appearances, he looked the part of the imposing 6-foot-2 ex-prison guard. Over time, he gained weight and began taking medication for bipolar disorder. He now projects a less intimidating presence in court, where he occasionally smiles softly and wears headphones at all times to correct longtime hearing loss. It was Barbara Freiberg, Lisa's mother, who discovered her daughter's and grandchildren's bodies the day after they were killed.As she struggled to open the mobile home's door, she glimpsed the mutilated body of her grandson, Zachary. She called her husband, then 911. It was Keith Freiberg, Barbara's husband, who entered the home. Blood and body parts were everywhere. Prosecutors said Covington stabbed the victims to death. He dismembered the 2-year-old. On top of their bodies, he poured dog food and bird seed. He also killed Duke, the family's German shepherd.Covington had met the 26-year-old a year earlier on the dating website Plenty of Fish. She had recently asked him to move in with her."Everybody makes mistakes in their lives. Lisa was no exception. But Lisa's mistake proved to be fatal," Maxim said.Contact Anna M. Phillips at [email protected] or (813) 226-3354. Follow @annamphillips.