A madman with a machete stabbed four people donating blood at a Virginia plasma center, police and reports said.

The mayhem unfolded at the Octapharma Plasma center in Petersburg around 4:40 p.m. Thursday, when the weapon-wielding man allegedly burst into the blood center, sending staffers and donors running for their lives, USA Today reported.

“The suspect possibly has a machete. Units use caution,” the dispatcher can be heard saying, according to the outlet, which cited a recording released by broadcastify.com.

Two victims remain hospitalized, with one in critical condition and one stable, Petersburg police tweeted. The remaining victims were treated and released.

Lt. Dustin Sloan said the suspect, Jairque L. Shannon, was arrested without incident once cops arrived.

“He was sitting in a chair waiting for us,” Capt. Emanuel Chambliss noted.

It’s unclear why he allegedly attacked.

Shannon, 20, was charged with three counts of malicious wounding and a count of animal cruelty. It was not immediately clear what kind of animal was injured or how.

Aggravated Assaults – Update

Jairque L. Shannon B/M, age 20 of Petersburg has been charged with Malicious Wounding (x3) & Animal Cruelty. Two victims remain hospitalized with 1 being listed in critical condition & 1 stable. The remaining victims were treated & released. pic.twitter.com/Lr2bh1vXjc — Petersburg Police (@PBurgPolice) July 5, 2019

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