A U.S. District Court judge yesterday lowered bond from $500,000 to $300,000 for one of two men charged with distributing cocaine on Capitol Hill. But the judge rejected an offer by the man's parents to pledge their Rockville home as security to obtain their son's release.

Judge Thomas F. Hogan said he believed that only a monetary bond would "provide assurance" that Troy Todd Jr. would not try to flee the area before his trial on the cocaine distribution charge.

Todd, 23, and Douglas Marshall, 27, were first arrested on cocaine charges last year. Both men subsequently left the country. They were rearrested in January in Australia, and were extradited from there last week.

On Thursday, Marshall, who had also been held on $500,000 bond, was released after the judge agreed to allow his parents to pledge their $418,000 Northwest Washington home and post a $50,000 surety bond to obtain their son's release. Todd's attorney, Stanley M. Dietz, argued yesterday that Todd should be released under similar circumstances.

But Hogan said, "I don't sense quite the same family relationship between Troy Todd and his family as I did with the Marshalls."

Hogan said that unlike Marshall, Todd had not been employed for the past five years but had supported himself through gambling and stock market speculation. He said Todd did not have the same level of education as Marshall, a law school graduate, and said he also was concerned about the fact that Todd has a pilot's license.

Assistant U.S. Attorney Daniel Burnstein described Todd yesterday in court as the "mastermind" of the cocaine distribution ring.

In order for Todd to be released under the $300,000 bond his family would have to raise $30,000 in cash and then put up $250,000 in property as security, Dietz said. He said that there was "no way" for Todd's parents to raise the $30,000 and that he would consider appealing Hogan's decision to the U.S. Court of Appeals.

Dietz said Todd's father, Troy Todd Sr., owns his own company called Aadco, and is the inventor of an air-purifying machine, which is used, among other places, in the D.C. Superior Court.