CHIPPEWA FALLS, Wis. – By the time he blasted his way into a stranger's house Sunday night, apparently to kidnap a young woman who lived there, Ritchie German Jr. had already fatally shot his mother, brother, and 8-year-old nephew at his family's home, authorities said.

German, 33, meticulously cleaned the first crime scene, arranging the bodies of his brother and nephew on a bed in a room that had been stripped of all other items. He lied about his mother's whereabouts when her employer called for her Saturday. He may even have slept at the family townhouse that night after scrubbing blood off the kitchen and bathroom floors, Chippewa County Sheriff James Kowalczyk said Tuesday.

A day later he drove to the home of a woman he was badgering with sexually suggestive texts and stepped to the front door armed with a shotgun. Moments later, she and German were dead and her parents were gravely injured.

In all, German fatally shot four people and then himself, leaving no clues about what triggered the violence. He was a loner who didn't have a steady job or friends, and his family said he suffered from serious mental illness

The only clues so far are similarities to the kidnapping of 13-year-old Jayme Closs and the murder of her parents, James and Denise Closs, in Barron County, Wis., in October.

As in the Closs case, the shooter chose a victim he didn't know, used a shotgun to blast into her home, and confronted and shot her parents. Kowalczyk said he considered it very possible that German intended to abduct Laile Vang, 24, who lived with her parents in Lake Hallie, Wis.

Kowalcyk said German had sent text messages of a sexual nature to Vang, who responded that she didn't know him. And as far as anyone knows, German, who lives in Lafayette, Wis., had never previously been to the Vangs' home.

He said that the attack "most certainly" resembles the Closs case, where Jake Patterson shot and killed Closs' parents with a shotgun and kidnapped Jayme, holding her captive for 88 days before she escaped.

"Why is he going armed to a residence he's never been to before? To our knowledge it's similar to the Closs situation," Kowalczyk said. "I'm not saying that was the motive, but I'm saying similar circumstances that happened in Barron County happened in Chippewa County."

At a news conference Tuesday, Kowalczyk detailed how German fatally shot his 66-year-old mother, Bridget German, 32-year-old brother, Douglas German, and his brother's son, Calvin Harris, at their Lafayette townhouse using a handgun, possibly as early as Saturday morning.

Then, on Sunday night, he traveled 4 miles by car to Lake Hallie where he shot and killed Laile Vang and gravely injured her parents, Teng Vang, 51, and Mai Chang Vang, 39. German then shot himself.

The crime scene in Lafayette left Sheriff Kowalczyk searching for answers. The bodies of all three victims had been moved to other rooms in the townhouse after the shootings, he said.

German positioned his brother and nephew in bed with their arms outstretched to their sides. Also odd, one of the two bedrooms had been completely emptied except for a single sweatshirt hanging in a closet.

Kowalczyk thought it might have been Bridget German's bedroom, and that Ritchie German cleaned it out after the shootings. Although German lived at the Lafayette townhouse, investigators found almost no personal belongings of his there, Kowalczyk said. He said investigators are considering the possibility that German had a place outside the family home where he stashed things.

When German arrived to the Vangs' home Sunday night, he left the car running outside as he walked to the front door armed with a shotgun and handgun, said Lake Hallie Police Chief Cal Smokowicz. German left a loaded 9-millimeter semiautomatic handgun and a pair of handcuffs in the car, Smokowicz said.

Investigators believe he walked up to the house and fired two shotgun slugs through a storm door and a third through the front door to get inside.

There, he shot at Teng Vang, who was struck in the hand. German then went on to shoot his wife, who also was wounded in the hand. Their injuries required amputations and their conditions Tuesday were unknown, though both are expected to survive, authorities said.

A GoFundMe page set up to pay for the Vangs' medical expenses describes Laile Vang as "a beautiful soul" and "the glue that held her family together."

German took his own life with the shotgun, with a handgun still in his waistband.

Law enforcement found two other family members hiding in the basement, and two others who had been upstairs during the shooting escaped by crawling out a window, Kowalczyk said.

A flood of 911 calls alerted police to unknown problems at the Vang residence about 10:22 p.m. Lake Hallie's two officers on duty arrived at 10:28, but by that time, all shooting had stopped, Smokowicz said. Ten spent shotgun shells were found in the home.

"The matter is pretty much over as fast as it started," Kowalczyk added.

After discovering the shootings in Lake Hallie, investigators ran the license plates on the 2016 Kia they found outside the residence and discovered that it belonged to Douglas German, who lived with his mother in the Lafayette townhouse. There, they found German's other victims. All three had been shot in the head with a handgun.

Investigators suspect they were killed Saturday because Bridget German's employer at a grocery store had called that day and left a message asking why she hadn't come to work. Ritchie German returned the call and said his mother was sick and was in the hospital, Kowalczyk said. A neighbor boy also had stopped by the Germans' home Saturday to ask if Calvin was home, he said. The boy said Ritchie German told him that Calvin was out shopping with his grandmother.

German's father, Ritchie German, Sr., has been estranged from the family for several years after divorcing Bridget. He said his son suffered from a bipolar disorder and told authorities that he once warned his ex-wife against giving their son money to buy a .357 Magnum handgun.

That weapon was not found in the family home, but Kowalczyk said other guns found there were likely the property of Douglas German.

Ritchie German was unemployed and has lived off and on with his mother in Lafayette since about 2004, Kowalczyk said.

His only criminal conduct took place in 2006 when his mother reported that he had threatened his two brothers with a shotgun. He was arrested for reckless endangerment and given probation in that incident.

Kowalczyk said investigators would like to hear from anyone who knows Ritchie German who could offer information connecting him with the Vangs, or other insights.

"We are looking for an answer," Kowalczyk said. "Right now, I gotta be honest with you, I don't have that answer."

Star Tribune staff writer Zoë Jackson contributed to this report.