Mao Lee testified Wednesday that she thought of St. Paul police officer Ruby Diaz as a sister. The two were good friends in college and had traveled together. Lee could trust Diaz, she said.

All of that changed when St. Paul police told Lee in May that her friend of more than 15 years allegedly had used her identity and personal information to wire $1,500 to a convicted felon in prison.

"I was angry," Lee said of her reaction to the news. "I felt that our friendship was taken advantage of."

Diaz, 38, is being tried in Ramsey County District Court on two counts of aggravated forgery and one count of identity theft, all felonies that would end her career as a police officer if she's found guilty. Diaz, of Lauderdale, is on paid administrative leave pending her trial.

Authorities allege that Diaz, a 14-year veteran of the police force, used Lee's personal information, including her name, birth date and home address, to wire $300 five times to Ramone D. Smaller, who is serving six years in St. Cloud prison for third-degree attempted murder. He has several pending felonies for drive-by shootings.

Smaller, 22 now, met Diaz when he was a student at Humboldt High School and she was the school resource officer.

But defense and prosecuting attorneys have agreed not to delve deeply into their relationship. Diaz's attorney, William Bulmer, said Tuesday that it was "irrelevant" to the case.

Assistant Hennepin County Attorney Andrew LeFevour, who is prosecuting the case due to a conflict of interest in the Ramsey County attorney's office, agreed not to pry into the details, describing it as "a friendship relationship" that carried on for several years.

But there were clues Wednesday that Diaz's association with Smaller was the cause of much grief at work.

Bulmer asked Lee if Diaz talked about Smaller in the context of her work.

Lee said yes.

Bulmer asked Lee if she was aware of the "ongoing harassment" Diaz suffered at work because of her relationship with Smaller.

No, Lee said.

Before Lee took the witness stand, Diaz's other attorney, Sam Savage, told jurors during opening statements that Diaz built strong relationships with students, and that those relationships sometimes continued outside of school.

"She loves making a difference in the lives of these kids," Savage said.

Diaz had wired money to another inmate once before, and was harassed at work, Savage said.

In his questioning of Lee, LeFevour tried to show that despite their close friendship, Lee never gave Diaz permission to use her information to create an e-mail address or accounts with Western Union and the Minnesota Department of Corrections to send Smaller money.

Bulmer was able to show that Lee and Diaz had a timeshare in Las Vegas and that Lee previously had allowed Diaz to use her credit card for that property and her personal information for an unrelated rental property.

Bulmer asked Lee if she had allowed Diaz to use her personal information for other purposes.

A long silence fell over Lee.

Bulmer asked if there was an earlier incident involving sending money to another inmate.

"No," Lee said.

After Lee's testimony, and outside the hearing of jurors, Bulmer, LeFevour and Ramsey County District Court Judge Leonardo Castro discussed evidence that Lee had allowed Diaz to use her information to send money to a different inmate.

LeFevour said the four-year-old incident was irrelevant to the current case.

Bulmer said it would show "ongoing consent." Castro said the line of questioning couldn't be allowed because Minnesota rules of criminal procedure don't allow the admission of a "prior bad act" to prove a current allegation.

Testimony is scheduled to resume Thursday morning. Diaz has said she will testify.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib