A doctor charged with stockpiling more than $1 million worth of machine guns and grenades was ordered Tuesday to remain in custody pending his federal trial.

U.S. Magistrate H. David Young said he was unconvinced that Dr. Randeep Mann, 50, would remain in the country if allowed to go free on bond. Mann is a naturalized U.S. citizen originally from India.

Mann, of London, Ark., faces charges of possessing machine guns that weren't federally registered in his name and possessing explosives only permitted for military use. After city workers uncovered a canister of 98 grenades near Mann's property last week, federal agents searched his home on March 4 and found 110 fully automatic machine guns and grenades made to be launched from military rifles.

"There's no doubt substantial pressure on (Mann) to flee," Young said, noting that agents also found $50,000 in cash during the search.

In his ruling, Young told Mann that he didn't have "an accurate picture of your financial wherewithal, and you also have contacts outside the country that would make it much easier than for another individual for you to flee the country."

Authorities said Mann, an internal medicine specialist, has a permit from the federal government to sell registered machine guns. Agents testified that Mann had 110 machine guns, but at least four were not federally registered in his name, as is required under the National Firearms Act.

They also said he kept weapons around the house, including loaded pistols in the bedroom and machine guns on the floor and in closets and safes.

"If you were shot with it, the round would cut you in half," said David Oliver, a special agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives, of a tripod-mounted sniper rifle found in Mann's house.

Mann's attorney, Blake Hendrix, said he may appeal Young's ruling, but has to first confer with his client.

Prosecutors had argued that the doctor's frequent travels outside of the country, extensive arms cache and family ties in India made him a flight risk and he should remain in custody.

But his wife, Sangeeta Mann, testified that her husband rarely left the country, and that her in-laws visited once a year for six months. Prosecutors had claimed that Mann left the country 121 times since March 2007, which Hendrix said would be difficult for a practicing doctor.

Mann was interviewed by state police on Feb. 4, the day a homemade bomb severely injured a West Memphis doctor who chairs the state Medical Board, which had disciplined Mann in the past. However, U.S. Attorney Jane Duke said Mann was not a target of the investigation into the bombing.

Mann was sanctioned by the state Medical Board on previous occasions, most recently in 2006 after several of his patients died from a lethal mix of drugs or an overdose of prescription medicine. Mann, who also faces a wrongful death lawsuit from a patient's family, maintained that the patients abused the drugs.