KANSAS CITY, Mo. — A man who federal prosecutors say they suspect in a Missouri decapitation killing was sentenced Tuesday to 35 years in prison for stalking Kansas massage parlor workers in an unrelated case.

Senior U.S. District Judge Gary Fenner told 69-year-old Robert Gross that his history of violence was “extremely disturbing” in sentencing him for the stalking and firearms charges, The Kansas City Star reported.

Although he has not been charged with homicide, Assistant U.S. Attorney Jess Michaelsen said Gross had long been suspected in the August 2016 killing of Ying Li whose body was found inside her burning Kansas City apartment. Federal law allows prosecutors to present information about uncharged crimes at sentencing.

Kansas City homicide detective Alane Booth said their investigation led them to conclude that Gross decapitated Li after he received a massage and had sex with her. Li was stabbed 18 times and her killer also cut off her fingers.

“This armed and dangerous criminal, with a history of stalking and violence toward women, will spend the rest of his life in prison,” said U.S. Attorney Tim Garrison.

Defense attorney John P. O’Connor declined to comment after the hearing, which lasted just under four hours.

In May 2019, Gross was found guilty on eight of the 10 charges that included stalking women who worked at massage parlors in Johnson County and in Lawrence. He was also convicted of possessing guns as a convicted felon and other firearms violations. Gross was acquitted on two counts of stalking.

Video played to jurors at trial showed Gross walking around a Lawrence massage parlor in 2017, at times naked, while berating a worker. The Journal-World reported that the video also showed Gross groping the woman.

The women told police their cars were keyed, screws drilled into their tires and their windows smashed out.

In connection with the incident at Lawrence’s Tea Spa Massage, Gross was charged Oct. 24, 2017, in Douglas County District Court with one count of aggravated sexual battery, a felony. He was arrested on the charge Nov. 7, 2017, posted a $5,000 bond and was released the same day.

That incident also prompted federal authorities to begin surveilling Gross, the Journal-World reported.

In the following months, Gross began purchasing handcuffs, ski masks, black shirts labeled with “SECURITY,” and guns from various businesses and individuals in the Kansas City area, according to federal court documents. Law enforcement closed in on him during a gun buy in a parking lot and made an arrest that December, the Journal-World reported.

Gross’ Douglas County case has been at a standstill since his arrest in the federal case.

Just before he announced the sentencing, Fenner asked Gross if he wanted to say anything. After speaking briefly with O’Connor, Gross said “Your honor I choose not to make a comment at this time.”