Image copyright Twitter Image caption Artur Samarin was seen posing with lawmaker Patty Kim in 2014 under his alias "Asher Potts"

A Ukrainian man has been arrested after he was found to be posing as a high school student in the US state of Pennsylvania for four years.

Artur Samarin, 23, enrolled at Harrisburg High under the name "Asher Potts" after his visa expired in 2012.

Police say he now faces charges of theft, identity theft and tampering with public records.

Mr Samarin, who was pretending to be 18, was said to be an active member of the school community.

Police said he was in possession of a driver's license using the Potts name at the time of his arrest, as well as a Social Security card obtained using a false birth date. They suspect his identity was fabricated, and not stolen.

Harrisburg School district official Kirsten Keys said her department was cooperating with the police.

Local news outlets say he was an active student at the school.

He was seen in May 2014 posing with state lawmaker Patty Kim, who tweeted a photo after presenting "Asher Potts" with a certificate introducing him as "a new member of the National Honor Society".

Marcel McCaskill, who joined Mr Samarin on a seven-week science and maths programme at Penn State told AP it was "totally mind-blowing" to find out about his real identity.

"Honestly, he was a very respectable guy. He was the perfect role model, someone you would want your son to look up to."

He was involved in food banks and cadet programmes, according to one report, and was even on the panel of a forum discussing youth violence in the greater Harrisburg area at the start of the year.