Police have finished the investigation into the quadruple homicide and suicide of a Lake Minnetonka family, releasing public documents this week detailing the September deaths.

In documents, police said they weren’t able to establish a clear motive for why Brian Short, 45, shot his wife and three children before turning the gun on himself. But investigators say that Short was stressed over financial issues with his Excelsior-based business and that he had checked insurance policies regarding death benefits.

South Lake Minnetonka Police officers discovered the deaths Sept. 10 after a co-worker contacted police, worried because Short’s kids hadn’t attended Minnetonka High School after Labor Day.

Police found Short’s wife, Karen, shot in the head next to a cordless phone, and their 17-year-old son, Cole, 15-year-old daughter, Madison, and 14-year-old daughter, Brooklyn, shot in their beds of the Greenwood house.

Brian Short was found in an underground garage with a self-inflicted head wound next to a chair, a shotgun manual and a Remington 12-gauge shotgun. All five family members died from single shots to the head, the medical examiner said.

Police sifted through e-mails, legal documents and several home safes, and tried unsuccessfully to access the home’s surveillance video to investigate the crime.

Short’s friends told police that he was stressed about his business’ finances and that he had checked in February whether insurance policies paid out after suicides. Neighbors told police that the family, often seen boating or hosting parties, had been quiet before the incident. And family members said Short was selling the house as part of downsizing.

Short, a nurse, founded AllNurses.com, which provides information and resources for the nursing profession. A co-worker told police that Short had been struggling with mental health issues but that he had started seeing a therapist and changed medications. His company had been sued recently, and he said he was worried about lost money from online advertising.

A receipt and surveillance video from the Gander Mountain store in Eden Prairie confirmed that Short bought the shotgun and two boxes of ammunition Sept. 6. Neighbors reported hearing possible fireworks that night or two days later.

A friend told police that he met with Short a few days before the incident and asked how he was doing. The friend said Short made a gesture with his hand in the shape of a gun, put it to his head and answered: “It’s just overwhelming.”