The State Patrol is investigating a threatening phone call allegedly made against a whistleblower who raised concerns about hospital payment practices by the Minnesota Department of Human Services.

DHS purchasing manager Paul Olson said he was at home about 10 p.m. Wednesday when he received the threat, which according to Caller ID was made from his own desk at work. A TV news piece on the concerns he raised aired until about 10:04 p.m., though the report didn’t name him.

“At 10:06,” he said, “the phone rang.”

He couldn’t identify the voice, which was muffled.

“You’re marked,” the voice said before the call was disconnected.

The State Patrol confirmed that it opened an investigation after a DHS employee — it wouldn’t name Olson — called the Capitol Security division at 10:26 p.m. Wednesday night and reported “a phone call of a possibly threatening nature.” A DHS spokesman declined to comment, other than to say that “we fully investigate any concerns that are brought to our attention.”

Olson raised objections earlier this year to several state Medical Assistance payment practices, including the fairness of an exemption granted to the University of Minnesota Amplatz Children’s Hospital from a 10 percent hospital payment rate cut. An internal DHS audit of the complaint was completed this month and found that state officials erred in granting that exemption to Amplatz without conducting a legal review of whether it was appropriate.

The issue regarding Amplatz appears one of inadequately worded legislation. On Thursday, Rep. Jim Abeler, R-Anoka, author of the 2011 bill including the hospital rate cut, said his intent was to exempt Amplatz along with three other pediatric hospitals in the metro area.

Those hospitals serve a high number of low-income children covered by public programs, Abeler said, so they would have been unfairly burdened by the cut, which was one of several made to balance the state budget in 2011.

Questions surfaced about the exemption for Amplatz because it is licensed as a part of the larger U Medical Center — so it could be viewed as a hospital unit rather than a stand-alone hospital — while the other three are licensed on their own as free-standing pediatric hospitals.

Olson claimed he has been treated differently at work since bringing his concerns and fraud claims to state and federal health care authorities earlier this year. He said he felt threatened by Wednesday night’s phone call.

“I don’t know what it meant,” he said. “It wasn’t good, though.”