A Philadelphia man who was cooperating with federal authorities after pleading guilty in a mortgage-scam case was indicted yesterday on murder-for-hire charges.

Mahn Huu Doan, also known as Bruce Doan, was arrested and held without bail pending a detention hearing scheduled for Wednesday in U.S. District Court.

Doan, 40, is accused of hiring a hit man to kill two unnamed individuals and mutilate a third. Neither the targets nor the hit man were identified by authorities, who provided only sketchy details about the case.

The bizarre twist of a cooperating witness' allegedly conspiring to commit murder while working with federal authorities had Doan's lawyers searching for answers.

"If they had told me he was conspiring to rob Fort Knox, I could believe it," said William Brennan, who has represented Doan for several years. "But murder for hire? That's totally incredible."

"He's all bluster," added Jeffrey Miller, who with his partner, Carmen Nasuti, also represents Doan. "A lot of bark, but no bite."

The defense attorneys said they hoped to get more details about the case at Wednesday's hearing. They declined to comment further, but said the new charges could affect Doan's cooperation agreement and scheduled sentencing in the mortgage-fraud case.

It could not be determined whether the murder-for-hire charge was connected to that case.

The three-page indictment alleges that Doan promised to pay a hit man, identified only as Person No. 1, to murder two individuals and "assault, mutilate, and maim a third victim."

Person No. 1 was described as "known to the grand jury," a designation sometimes applied to an individual who is cooperating and who has testified before a grand jury.

The indictment alleges that Doan promised cash and a residence to the alleged hit man, that he directed associates to photograph and conduct surveillance of the home of two of the targets and the business office of one of them, and that he helped arrange the purchase of a firearm in New Jersey to be used in the murders.

The investigation, which is believed to include phone wiretaps, focused on events in April and this month, according to the indictment.

Doan is scheduled to be sentenced in the mortgage-fraud case on June 16, but that sentencing will likely be postponed.

In that case, authorities said Doan, based in South Philadelphia, headed a group of individuals who systematically defrauded banks by lying to obtain federally backed mortgages.

The scheme, which extended from March 2001 to February 2003, involved "the purchase and sale of approximately 180 properties in and around Philadelphia," according to court documents.

Authorities charged that Doan and his associates used "false identities and inflated appraisals" to fraudulently obtain mortgages on properties that they bought and sold.

Doan was indicted with nine codefendants in July 2006 and agreed to cooperate and plead guilty a few months later. He has been free on $50,000 bail.

He pleaded guilty to conspiracy, wire fraud, making false statements, and identity-theft charges.

Authorities alleged that he grossed more than $1 million through the scam, but he disputed that figure, according to a plea memorandum.

Contact staff writer George Anastasia at 856-779-3846 or ganastasia@phillynews.com.