CHICAGO (CBS/AP) — A Wisconsin man suspected of killing four people before taking his own life might have been trying to imitate the kidnapping of 13-year-old Jayme Closs and the murders of her parents.

Chippewa County Sheriff’s police said 33-year-old Ritchie German Jr. shot and killed his mother, brother, and 8-year-old nephew at their home in Lafayette over the weekend. He then used a shotgun to force his way into another home about 10 miles away, where he killed 24-year-old Laile Vang and wounded her parents before killing himself.

The Closs kidnapping and murders happened under similar circumstances last fall in Barron County, just 40 miles away.

“It was kind of similar in nature. In the Closs investigation, the door was breached, a shotgun was used. Mr. Closs was shot. Mrs. Closs was shot. Very fortunate in this case is that the Vangs are going to survive from their injuries, but it could have been very very similar in nature as to what happened,” Chippewa County Sheriff James Kowalczyk said. “Again, I’m not saying that that was the motive, but it’s just unlikely that some of the same incidents up in Barron County happened in Chippewa County.”

Ritchie German is suspected of killing his mother, brother, and nephew, and then a stranger he’d been harassing before taking his own life. (Credit: Chippewa County Sheriff)

Investigators said German left his car running outside the Vang’s home and had handcuffs and a loaded handgun clip inside the vehicle. That led police to suspect he might have been trying to imitate the home invasion and abduction at the Closs home last fall.

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, asking anyone who had been in contact with German in the last week to call the sheriff’s office.

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, but 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. They remained hospitalized Tuesday but are expected to survive. None of the four people, including three children, who managed to hide in the home during the attack were 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.

Ritchie German called the grocery store where his mother worked on Saturday morning and said she was sick and in the hospital, Kowalczyk said. And a neighborhood boy who played with Calvin Harris knocked on the door and asked if Calvin was home, but German told the boy that Calvin was shopping with his grandmother.

Ritchie German Sr., who was divorced from Bridget German, told the Star Tribune that he was shocked to learn of the killings and that his son Ritchie had struggled with mental illness. He said his son lived with him from 2005 to 2014 and worked for just one year during that time, at a Menards warehouse. He said his son stayed in his bedroom most of that time.

German Jr. was convicted of disorderly conduct in 2006 and sentenced to a year of probation after the sheriff said he pointed a gun in the direction of his brothers. But Kowalczyk said, “We don’t have a lot of history with him.”

Closs escaped from her abductor almost three months after she was kidnapped, and was reunited with her aunt and other relatives. In May, 21-year-old Jake Patterson was sentenced to life in prison after pleading guilty to murder and kidnapping.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)