A gunman who opened fire on a Wisconsin trail bridge last month, killing three people and wounding another before taking his own life, was drunk, had stopped taking medication for depression and had a history of suicidal and sometimes homicidal thoughts, according to a police report released Thursday.

Police concluded that Sergio Valencia del Toro had an argument with his girlfriend on May 3, then armed himself with two handguns, rode his bike to the Trestle Trail bridge across Little Lake Butte des Morts in the eastern Wisconsin city of Menasha and randomly shot at people.

Del Toro, 27, fatally shot Jonathon Stoffel; Stoffel's 11-year-old daughter, Olivia; and Adam Bentdahl. Stoffel's wife, Erin, was shot multiple times and survived. Del Toro had also shot at others who were not hit, the report said.

Records from del Toro's previous military service showed he had either sought or had been ordered to a number of behavioral health interventions while in the U.S. Air Force, the report said.

His initial contacts with medical and behavioral personnel began in 2009 over concerns about alcohol abuse. In October 2010, del Toro went to a clinic and indicated he was concerned about the increased frequency and intensity of his mood swings, the report said. Between 2010 and his discharge from the military in 2014, del Toro had about 14 appointments with behavioral health personnel to talk about his depression and suicidal thoughts, according to the report.

In a disability benefits questionnaire he filled out as a veteran in November 2014, del Toro wrote about hallucinations and "seeing things out of the corner of his eye that he knows are not there." He also reported having suicidal and homicidal thoughts about four years earlier. He stated that during that time he was thinking, "If I'm going to take myself out, I might as well take other people with me."

Del Toro said his depression began when he was 7 or 8 years old, the report said.

Haylie Peterson, del Toro's girlfriend, told investigators he at some point stopped taking his medication for depression and that his behavior was irrational in the days leading up to the shooting. The couple had recently called off their wedding and got into an argument about two hours before the shooting, according to police.

A toxicology report showed del Toro's alcohol level was .24 at the time of the shooting, three times the legal limit to drive.

According to the report, numerous people said they saw del Toro standing on the bridge staring off into space for 45 minutes to an hour. After shooting Bentdahl, del Toro stood over him on the bridge pavilion and told the Stoffel family "something to the effect of, 'You didn't see anything," then started shooting them, the report said.

Erin Stoffel told police she and her husband were shot almost simultaneously. She said she saw her husband fall, then Olivia. She said her husband then said "something about forgiving the shooter," the report said. Erin Stoffel then grabbed the hand of daughter Selah and yelled at son Ezra to get off the bridge as they all ran to safety.