(CNN) -- A Virginia Tech student was arrested Monday after police said he had an assault rifle and was trying to buy 5,000 rounds of ammunition.
Yunsong Zhao, 19, has been charged with illegal possession of an assault rifle while not being a US citizen, according to an arrest warrant obtained by CNN affiliate WSLS.
Police say Zhao had bought a former police vehicle -- which still had police markings -- and installed a special bumper to the car. The freshman student had also researched bulletproof vests, the document states.
Virginia Tech Police Chief Kevin Foust said Zhao was arrested without incident following a "lengthy investigation."
No more details about his arrest or the investigation have been released.
Zhao is from China and had been living in the area for about six months, the warrant said.
He remains in custody at the Montgomery County Jail without bail, officials said.
CNN has attempted to reach Zhao's attorney, but did not receive a reply late Tuesday night.
In a statement, university officials said unsubstantiated rumors had been circulating on campus about an individual stockpiling weapons and that Zhao's arrest was not linked to those rumors.
"As always, the safety of the Virginia Tech community is the top priority of the university and its police department. Police remain vigilant at all times and work around the clock to keep our campus safe," the university said in a statement.
This April marks the 11-year anniversary of the 2007 campus shootings at Virginia Tech where a 23-year-old student shot and killed 32 people before taking his own life.
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