Blair County Prison, Associated Press
This undated photo provide by the Blair County Prison shows eighteen-year-old Vladislav Miftakhov. Miftakhov, a Pennsylvania college student from Russia, was arrested Friday, Jan. 24, 2014 and charged with building a suspected bomb. Police say he had bomb-making and marijuana-growing materials in his rented bedroom near the Penn State-Altoona campus.

PITTSBURGH — A former college student facing a two-year prison sentence for building bombs without a federal license in his off-campus Pennsylvania apartment tells a judge he now recognizes his "dangerous hobby" was "reckless and childish."

Nineteen-year-old Vladislav Miftakhov is scheduled for sentencing Friday before a federal judge in Johnstown.

In a two-page letter apologizing for his actions, Miftakhov tells the judge he realizes the danger he posed, even though he never intended to hurt anyone.

The San Carlos, California, man has been jailed since police acted on a landlord's tip that Miftakhov was growing marijuana in his apartment near the Penn State-Altoona campus on Jan. 24. Police found bomb-making materials, including an unexploded device containing about a half-pound of volatile chemicals in the apartment about 85 miles east of Pittsburgh.