The federal government has expanded its investigation of Minneapolis money manager Trevor Cook's $190 million Ponzi scheme to include a number of his former business associates, according to recently unsealed court documents.

Investigators have seized evidence routed through network servers in Golden Valley and in Colorado Springs, seeking information related to at least 21 business entities that may have been involved in his scheme, according to search warrants filed in the case.

Cook pleaded guilty in April to mail fraud and tax evasion charges, admitting he bilked about 1,000 investors -- mostly retirees -- in an international currency investment scheme. He remains in the Sherburne County jail as he awaits sentencing, and is required by his plea agreement to help investigators and a receiver who is trying to locate investor assets.

Court documents unsealed earlier this month show that investigators are targeting e-mails, contact lists, appointments, pictures and file attachments routed through e-mail accounts used by Cook; his younger brother Graham, a computer expert; Tom Richardson, the former chief operating officer at Cook's firm, Oxford Global Advisors; and Jason (Bo) Beckman, a former partner of Cook's who runs an investment advisory firm called the Oxford Private Client Group.

None of them could be reached for comment Tuesday. Beckman's attorney, W. Patrick Judge, declined to comment.

Eileen Rice, the FBI agent who spearheaded the investigation of convicted Minnesota swindler Tom Petters, described the government's wide-ranging and ongoing investigation of the Cook scheme in a 28-page application for two search warrants in late May.

Her narrative shows how Cook threw his money around to buy favors he needed to keep the scheme afloat, and when it finally faltered, opted to keep his investors in the dark even as he continued taking their cash.

Gary Saunders, a California attorney and business partner of Cook's, told investigators in January that he met Cook in March 2008 and sold him two Panama condominiums that were under development, Rice said. Cook agreed a few months later to become a 50 percent owner with Saunders and another partner in a Panama City hotel and casino development, and made payments of $1.1 million a month until his money began to run out about a year later.

Saunders said because Cook was such a good client, he agreed to write a letter at no charge certifying that Cook had $4.4 billion in assets under management. Saunders did this though he was not an auditor and had no background in finance, Rice said.

She said Saunders reviewed some of Cook's client files in Minnesota and visited two Swiss firms where Cook bought his trading technology and placed his currency trades. He spent less than two hours at both locations, she said.

Cook spoke with investigators in a series of interviews after he pleaded guilty. He said he'd been making money trading in currencies until late 2007 or early 2008, Rice said.

About that time, he said the owners of Crown Forex SA in Switzerland, where he'd placed his trades, asked him not to make any large withdrawals or it would force the company into bankruptcy. Cook, a part-owner of the firm, said he agreed, leaving about $100 million of his investors' money in the accounts.

"Cook said, 'We just lied to them,'" she said.

Swiss authorities forced Crown Forex into bankruptcy and are continuing to unravel its accounts.

Richardson was Cook's chief operating officer from June 2008 through July 2009, when the investment scheme collapsed, Rice said. A former employee told investigators that Cook had said Richardson had to review all withdrawal requests and stayed in close e-mail contact with Cook.

Cook said he met Beckman in 2006, and that Beckman -- an equities specialist -- liked his currency investment strategy enough to put some of his clients' money into the program, Rice said. Beckman and Cook also had been partners at one time in Oxford Global Advisors, and each had offices in the Van Dusen mansion just south of downtown Minneapolis.

An IRS criminal investigator working on the case has reviewed a set of e-mails between Cook and some unidentified cohorts in which they discussed trades, fund transfers, meetings and "falsification of financial records," Rice said. At least one of the e-mail accounts ends with the Internet domain name, she said -- an account associated with Beckman's firm.

Dan Browning • 612-673-4493