MINNEAPOLIS (AP) — Three teens were charged with murder Friday in the brutal death of a 79-year-old central Minnesota woman who was ambushed in her house, forced to write a check to her attacker, choked, then stabbed repeatedly with a sword-like knife, according to details in a criminal complaint.

Brok Junkermeier, 19, was charged with intentional second-degree murder, without premeditation, on Friday in Kandiyohi County District Court. Two other teens — ages 16 and 17 — were charged as juveniles. They each face two counts of aiding and abetting murder.

The charges say one of the teens believed Lila Warwick had more than $40,000 in a safe and they had been planning to kill her and steal her money for some time.

Warwick was found in her Wilmar home Monday night after authorities went to check on her welfare. Someone called authorities after she failed to show up at a meeting at Redeemer Lutheran Church, where she was a volunteer.

“Upon entering into the garage and home, deputies found evidence of homicidal violence and found the body of Ms. Warwick who was deceased,” one of the juvenile petitions said. Preliminary autopsy results showed she died from complex homicidal violence involving multiple stab wounds and strangulation.

On Tuesday and Wednesday, two witnesses told authorities they heard Junkermeier talk previously about killing Warwick and stealing her money, but both thought he was joking. One of the witnesses said that the day after the killing, Junkermeier came to him and talked about the burglary and attack.

According to the charges, Junkermeier told his friend that he and another teen drove to Warwick’s house early Monday. Junkermeier had previously obtained a key to get into Warwick’s garage, and went inside wearing a mask and gloves while the teen stayed in the car as a lookout. Junkermeier waited two hours for Warwick to enter the garage, then ambushed her and slashed her hand with a 20-inch knife.

Junkermeier told his friend that while Warwick was bleeding, he forced her to access her bank account online and write him a check for $1,500. Prosecutors say Junkermeier later deposited that money into his account.

Junkermeier told his friend he then began to strangle Warwick, and when he saw she was not dead, he stabbed her multiple times then brought or threw her into the basement, the charges said. Later that day, Junkermeier and one of the teens returned to Warwick’s house and took a safe.

The charges said Junkermeier confessed to the killing when he was arrested Wednesday, and told police where to find the knife. Bloody gym shoes, a safe and 30 $1,000 savings bonds in Warwick’s name were found at Junkermeier’s house, the complaint said.

It was not immediately clear if Junkermeier had an attorney. A message left with his father was not returned. Junkermeier’s bail was set at $2 million, or $1 million with conditions.

Junkermeier, a 2012 graduate of Willmar High School, has some theft-related charges on his record and was on probation at the time of Warwick’s death.

The West Central Tribune reports he was arrested at the newspaper’s mailroom, where he worked part-time.