A Wisconsin man killed three of his family members before blasting his way into the home of a stranger he had been harassing through text messages and killing her, authorities said Tuesday, speculating that he may have been trying to imitate last year's home invasion and abduction of teenager Jayme Closs.

Ritchie German Jr., 33, shot his mother, brother and 8-year-old nephew at their home in Lafayette, likely on or before Saturday morning, Chippewa County Sheriff Jim Kowalczyk said at a news conference. On Sunday night, he drove about 10 miles to the Lake Hallie home of 24-year-old Laile Vang, blasted his way inside with a shotgun, and shot and wounded her parents before killing her. He then killed himself in the home, where several others were hiding, the sheriff said.

German left his car running outside of the Vangs' home and had items in it — including handcuffs and a loaded handgun clip — that led investigators to believe he could have been planning to imitate last October's deadly home invasion and abduction of Jayme from her family's home just 40 miles away, the sheriff said. In both cases, the attackers used guns to blast their way into the homes.

However, Kowalczyk said investigators may never know why German carried out the attacks.

“What was the motive? Why did this happen? I don't have the answer,” he said.

A couple of days before the attack, German sent unsolicited sexual texts to Laile Vang, but she apparently didn't know him and replied “Who is this? I don't know you,” authorities said. Kowalczyk said there is no evidence that the two had ever met.

Chief Deputy Chad Holum said authorities are going through about 10 cellphones and are working to find out how German got Vang's phone number. They suspect he may have gotten it off the Internet.

Vang's parents, 51-year-old Teng Vang and 39-year-old Mai Chang Vang, suffered defensive wounds and each had to have an arm amputated, authorities said. Four people, including three children, hid in the home during the attack and were not hurt.

German was a loner who was often unemployed and who occasionally lived at the Lafayette home where he gunned down his 66-year-old mother, Bridget German, his 32-year-old brother, Douglas German, and his brother's 8-year-old son, Calvin Harris, Kowalczyk said. All three were shot once in the head with a handgun.