An artist's rendering of human-size bedbugs riding on a train. Mike Nudelman UPDATE: The MTA inspected the 7 train in question and found no evidence of bed bugs.

According to a tipster who sent a horrifying account of his morning commute to Business Insider on Wednesday, bedbugs have been spotted on New York City's 7 train. The Metropolitan Transportation Authority, which runs New York's subway system, told us it is investigating the report.

This would be the third subway line to have a bedbug sighting in the past week.

"I am a regular 7 line rider in New York. I take the line every morning from Woodside to Bryant Park. This morning, I noticed them coming out from under the seat to feed on people's legs," Kedem Deletis wrote in an email to Business Insider. "I was on the 7 express train, which arrived at Bryant Park at 10 a.m. The cart I was in was one or two carts behind the center operator cart."

Early last week, subway cars on the N line were fumigated after bedbugs were found on board. Days later, more bedbugs were found on the N and a rider reported seeing the creatures on a 5 train.

Deletis told Business Insider he called the MTA, which runs New York's subway system, and "was treated pretty bad with the person on the line asking me what kind of proof I have."

"What exactly should I have done? Raised a panic on the train and have people screaming and hurt?" Deletis asked. "Maybe captured one of these bedbugs and risk bringing one home?"

Deletis said he was certain the insect he saw was a bedbug because he had an infestation in his building "about four years ago" and "that nightmare experience made every resident an expert."

MTA spokesman Kevin Ortiz said the MTA would "follow up" on Deletis' report. Deletis received an email from Art Kelly, an MTA email and customer correspondence manager, on Wednesday afternoon.

"This is in response to your call regarding bedbugs on subway trains," Kelly wrote. "Please be assured that pest-control personnel will continue to be dispatched to trains and employee crew rooms where bedbugs have been reported. They will inspect for bedbugs and fumigate as necessary."

Another MTA spokesman, Adam Lisberg, told Business Insider officials follow up on all reported bedbug sightings in the subway.

"It is impossible to check all 5.5 million daily subway customers for bedbugs before they enter the system, but when we get a report we investigate immediately and fumigate if necessary," said Lisberg.

According to Ortiz, the last time the MTA had multiple bedbug problems in the subway was 2008, soon after infestations began a resurgence in New York.

"We previously had an issue with bed bugs right around the time in 2008 when the city first noticed there was an issue. Bedbugs were sighted on wood benches in a couple of stations," Ortiz said.