A Las Vegas company received and completed a contract to clean the crime scene at the site of the worst mass shooting in U.S. history.

A Sky Flyer amusement ride and vendor booths sit frozen in time at the site of the Route 91 Harvest mass shooting at the Las Vegas Village festival grounds in Las Vegas. (Richard Brian/Las Vegas Review-Journal)

WASHINGTON — A Las Vegas company received and completed a contract to clean the crime scene at the site of the worst mass shooting in modern U.S. history.

The FBI contracted for cleanup and decontamination of the Route 91 Harvest festival venue after the crime scene investigation was completed following the tragedy that left 58 dead and hundreds wounded.

An FBI spokeswoman in Las Vegas said Tuesday the work was completed and the property turned over to MGM Resorts International.

A fixed-price contract of $200,429 was issued to BioOne Las Vegas LLC, according to documents filed Oct. 17 by the Justice Department and the FBI.

The gunman used his 32nd-floor Mandalay Bay suite as a sniper’s nest to fire at the 22,000 people attending the outdoor country music concert. He equipped 12 semi-automatic rifles with bump stocks, devices that accelerate the rate of fire to simulate automatic weapons. He had 23 weapons in his suite and others at homes in Mesquite and Reno. He died of an apparently self-inflicted gunshot wound.

A local investigation continues to search for a motive for the shooting. The FBI is assisting the Metropolitan Police Department in the probe.

Laboratory analysis of evidence collected at the crime scene in Las Vegas is being conducted by the FBI in Quantico, Virginia.

Documents show the FBI completed the crime scene investigation and issued a contract to treat and sanitize a location roughly 15 acres in size.

In its requisition document, the FBI said “the government had responsibility to ensure the site was rendered safe for human use.”

Treatment services included the removal and disposal of non-contaminated and contaminated debris, including turf and carpets, and sanitation of concrete, vendor booths, bleachers and fencing.

“Due to the magnitude of the violence which occurred on the site, the size of the facility, and the lengthy time required to conduct the scene investigation, the site became a significant biohazard,” the FBI requisition document stated.

Because of the hazard, the FBI allowed one person on site under escort to provide a cost estimate. Although four companies were contacted, the FBI selected BioOne.

The FBI disclosed the information in the requisition document required by law because the service was not let out for bid and open competition. The FBI cited security and urgency in bypassing a bid process.

BioOne is a business that provides crime and trauma scene cleaning. Contacted by telephone, James Herold of BioOne did not comment on the contract.

About 20 vendors were on-site at the 15-acre festival grounds when the shooting started during a performance by Jason Aldean.

In his first interview since the shooting, Aldean told NBC’s Today on Tuesday the horrific event on Oct. 1 is “something I’ll never forget.”

“I hope everybody can start to heal. Some of the stuff you’ll never get over. I hope it gets better for everybody as time goes on,” he said.

Contact Gary Martin at gmartin@reviewjournal.com or 202-662-7390. Follow @garymartindc on Twitter.