MADISON, Wis. -- The primary suspect in the November beating death of a man at a city park remains in custody but has yet to be charged.

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Michael Voltz, 46, is in the Dane County Jail awaiting sentencing for violations of his parole or extended supervision.

Dane County District Attorney Brian Blanchard said he's still waiting for the results of a "scientific" test before making a charging decision.

Meantime, Voltz is scheduled to be sentenced in about three weeks for breaking parole. His parole agent is recommending that he go back to prison for two years.

State Department of Corrections representatives said the parole revocation is based on his past battery record and his arrest shortly after Mark G. Johnson, 37, of Madison, was found dead at an East Side park more than two months ago.

A state parole revocation summary said Johnson suffered 15 broken ribs and died from severe face and head trauma.

In the summary report, Voltz's former girlfriend, Debra Tepp, said Voltz beat Johnson because he was jealous the two were dating.

Authorities said Tepp told Madison officers that "Voltz kicked (Johnson) two or three times in the head" with "a lot of force."

Authorities said she went on to say that she tried to intervene but Voltz shoved her out of the way, causing her to fall and injure herself.

She said she then "picked Johnson up off the shelter floor" and that "he was having difficulty breathing when Voltz grabbed (him) by the hair and pulled him down to the floor again" to continue the beating, according to authorities.

Authorities said Voltz later told a friend he "did a tap dance" on Johnson.

A friend of Voltz, Kevin Harrolle, reportedly told police that he came to the park to pick up Tepp and Voltz and thought Johnson was off "licking his wounds."

The trio then went to a bar and Voltz and Harrolle had beer, police said.

Police said that later they drove back to Lake Edge Park, where Harrolle found Johnson's body in a grassy area and called 911. Tepp and Voltz took his car and drove off, according to authorities.

The county's 911 Call Center investigated the alleged mishandling of city police dispatch to that scene.

An hour and a half before Harrolle's call to report a lifeless body, park neighbors had twice called a non-emergency line to ask police to check out a disturbance at the Lake Edge Park shelter. The second call came in at about 9:30 p.m. on Nov. 3.

The caller said: "We just called in a complaint about Lake Edge Park on Lake Court about some folks just hanging out in the shelter and it seems like the volume and the violence is escalating in terms of their words. So if you could send someone out, we'd appreciate it."

In a follow-up report, Dane County officials said they found multiple errors in the way 911 operators handled the two non-emergency calls. They said one key mistake was not upgrading the call's priority after the second call came in.

Voltz left prison early last year with a record of battery and drug use.

While on high-level supervision, corrections officials said Voltz tested positive four times for drugs the first six months he was out and was referred for programming.

The revocation summary said that five months out of prison, Voltz had two Madison police contacts: one for sleeping in a car and another charge of creating a disturbance. In that incident, a store clerk told police that, "An intoxicated customer got irate and told an employee to 'come to the park to settle things.'"

The next month, in August, authorities said Voltz had two more police contacts with park ties: one was for being at a park after hours and the other for witnessing a park fight.

State corrections officials said Voltz's supervision was handled appropriately.