By Casey Sullivan

Oct 26 (Reuters) - A former Deloitte & Touche LLP accounting partner was sentenced to 21 months in prison on Friday for insider trades in stocks of his corporate clients including Best Buy Co Inc, Sears Holdings and Walgreen Co, according to the U.S. Department of Justice.

Thomas Flanagan, 65, who pleaded guilty in August to one securities fraud count in federal court in Chicago, was also fined $100,000 and ordered to perform 200 hours of community service after he is released from prison.

Flanagan will begin his prison sentence on Jan. 15.

Joel Levin, a partner at Perkins Coie in Chicago who represents Flanagan, declined comment late Friday. Assistant U.S. Attorney Jason Yonan, the lead prosecutor in the case against Flanagan, did not immediately respond to a request for comment. A Deloitte spokesman did not immediately return a request for comment.

According to his plea agreement, Flanagan illegally bought or sold shares and options in Best Buy Co, Sears Holdings Corp and Walgreen Inc, on whose accounts he was Deloitte's advisory partner, and Motorola Inc, where he was on a non-audit engagement team.

Flanagan's scheme was based on advance knowledge of quarterly results for Best Buy, Sears and Walgreen; a 2007 purchase by Walgreen of pharmacy services company Option Care Inc; and a cost-cutting plan and weak mobile phone sales report for Motorola.

Flanagan's illegal trades took place between December 2006 and May 2008 in accounts he controlled and in the names of his wife and two sons. The defendant also gave tips to a family member who made at least $58,000 of illegal profit, the plea agreement said. The family member was not charged.

The case is U.S. v. Flanagan, U.S. District Court, Northern District of Illinois, No. 12-cr-00510.

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