Dorothy Noga was playing amateur detective with a suspected child killer in 1981 when he decided she had learned too much.

Noga was working at Comfort Massage Studio in St. Paul when Stuart Knowlton arrived sometime after 2 a.m., pushed her into a chair and pressed his face into hers. She had been working with police to solicit and tape a phone confession from him.

" 'Take a look, because it's going to be your last,' " Noga recalled him saying. " 'I'll show you what she went through.' "

Knowlton was suspected in the Nov. 10, 1981, kidnapping and strangulation of 6-year-old Cassie Hansen, whose body was found the next day in a dumpster behind an auto repair shop on Grand Avenue. He stabbed Noga in the neck, behind the ear, slashed her throat and stabbed her in the buttocks during a 20-minute attack that nearly killed her.

On Wednesday, the 36th anniversary of the attack, St. Paul Police Chief Todd Axtell recognized Noga and three retired officers for the first time for their roles in solving Hansen's murder.

"Life was never the same for that generation of kids in this city," said retired officer Pat Scott as he received the chief's award for merit. "It shook us to our core. … Dorothy Noga did so much more than could be expected of anyone. She is the hero in this room."

Scott responded to the attack on Noga, and is credited with saving her life by applying pressure to the wounds. Retired Sgt. Richard Klein and officer Jim Groh were recognized for responding to the original call about Hansen's disappearance, working with her family to broadcast her photo on TV that evening and developing early leads about Knowlton.

Axtell said that the officers and Noga had not been formally recognized for their contributions until Wednesday.

Cassie disappeared after she went to find a bathroom at Jehovah Evangelical Lutheran Church in St. Paul.

Noga was working that night when Knowlton stopped by the massage parlor about 10 p.m. posing as a shoe salesman. He left a business card and a phone number. She thought nothing of him.

Noga said that as a mother of four young children she felt compelled to call police the night of the disappearance and report a massage client who had previously made comments about children. That's when she learned that they were considering Knowlton.

Noga volunteered to call Knowlton against police wishes, and said she was able to solicit a confession that night.

As the investigation unfolded — investigators interviewed more than 600 people and considered more than 100 suspects — Noga worked with police and had more phone conversations with Knowlton.

Knowlton was charged in Hansen's murder 10 months after the attack on Noga, and was convicted of first-degree murder in 1983. He was given a life sentence and died of natural causes in prison in 2006.

Two of Cassie's three sisters, Brittany Koller and Ashley Withrow, attended Wednesday's event, meeting and thanking Noga and the officers for the first time. They said their parents and older sister, who was Cassie's only sibling at the time of the disappearance, lived out of state and could not make the event. Their aunt, Kathy White, and first cousin, Joe Slagle, were among other relatives in attendance.

"It's an amazing feeling to meet those people," Koller said.

Slagle, who was 5 when Cassie died, said the crime left a lasting impact on how he raises his three children, ages 7 to 15.

"Even to this day, I can't let them go to the bathroom by themselves" in public places, he said.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib