LETTER

Ohio State Police Officer Alan Horujko shot and killed Artan.

As Burrier continued to read, he came across the powder.

"Once I realized what it was, I didn’t take a long time putting it in a sealed envelope," said Burrier, who did not read the letter in its entirety.

Columbus firefighters sent a hazmat team to the printing plant Wednesday in response to a 911 call, a standard procedure when an unknown powder is discovered in an envelope or a package, said Rebecca Diehm, spokeswoman for the Columbus Division of Fire.

The FBI's Joint Terrorism Task Force and Weapons of Mass Destruction unit responded. Field testing of the powder came back negative for toxic substances, said Todd Lindgren, a spokesman for the FBI office in Cincinnati, which oversees Columbus. Additional lab testing is still pending, he said.

"We take these matters very seriously. Sending threats, substances in the mail is a federal offense with strict penalties," Lindgren said. The maximum federal sentence upon conviction Donald Burrier, security manager for The Dispatch

could be up to 20 years.

First responders told Dispatch employees that they suspect the letter came from a 34-year-old male inmate from Lancaster serving a prison sentence for numerous robbery charges. As of Wednesday afternoon, he had not been charged in this case. Ohio law requires that all outgoing inmate mail be "clearly identified by the sender's name, institution number and return address."

"Any outgoing mail not so identified may be opened and read for the purpose of identifying the sender," per Ohio law. It's unclear why the envelope sent to The Dispatch without a return address was not opened in this case.

"I can't comment or provide additional information because there's an ongoing criminal investigation," said JoEllen Smith, a spokeswoman for the Ohio Department of Rehabilitation and Correction.

The inmate, who is scheduled for release in 2038, has a track record for sending threatening letters.

In 2015, he sent Franklin County judges

threatening letters containing a powder that he claimed was anthrax. The incidents led to the evacuation of the Franklin County Common Pleas Courthouse and action by hazardous-materials crews.

He sent the letter from the Southern Ohio Correctional Facility in Lucasville to Common Pleas Judge Kim Brown. The letter expressed disapproval with the judge's handling of his case and warned that death would result from the enclosed powder. The substance turned out to be vitamin C.

The incidents led to convictions of possession or use of a hoax weapon of mass destruction, retaliation, intimidation and inducing panic.

The letter to The Dispatch comes less than a week after the Circleville Herald newspaper received a threatening letter targeting staff. That envelope was also filled with white powder, Circleville police said in a Facebook post.

The letter said the envelope contained fentanyl, a powerful prescription painkiller that is sometimes mixed with heroin, Circleville police said. However,

“Once I realized what it was, I didn’t take a long time putting it in a sealed envelope.”

investigators have not confirmed that the substance is fentanyl.

Last week, Ohio State University received a threatening letter with a suspicious substance at Bricker Hall, where the president's office is housed, said Dan Hedman, director of marketing and communication for the university. The FBI is also handling that case, which remains under investigation.

When Hedman was asked about the content of the university's letter and whether the 2016 attack was referenced, he declined to comment.

Several judges throughout Ohio also have received threatening letters containing white powder in recent days, The Associated Press reported Wednesday.

Among them was a letter sent to Cuyahoga County Common Pleas Court Judge Nancy Margaret Russo.

Russo told Cleveland.com that the letter contained death threats and was signed by a man serving a prison sentence.

It's unclear whether all of the recent cases are connected.