The secret romance was as unlikely as they come — between a 38-year-old St. Paul cop with no marks on her record and a 21-year-old gang member imprisoned for attempted murder and newly charged in several unusually violent drive-by shootings.

So when it came to light in criminal charges Friday that officer Ruby Diaz allegedly assumed another woman’s identity and wired $1,500 to inmate Ramone D. Smaller, even longtime veterans of criminal cases were stunned.

“I’m astounded,” said attorney Craig Cascarano, who represented Smaller in the earlier case. “I’ve been doing this for 39 years. I do this all over the country. I’ve never had a case like that.”

Diaz, of Lauderdale, was charged in Ramsey County District Court with two counts of aggravated forgery and one count of electronic use of false pretense to obtain identity.

Smaller, who is serving six years in St. Cloud prison for third-degree attempted murder, was newly charged Friday in Ramsey County District Court with 10 felonies for three drive-by shootings in October.

Diaz worked as a school resource officer at Humboldt High School from 2002 until her assignment to the gang unit in 2005, according to police records. She resumed her post at Humboldt in 2008 until she was placed on administrative leave because of the criminal investigation into her actions.

Authorities discovered Diaz’s alleged crimes while investigating Smaller’s role in the drive-by shootings, Chief Thomas Smith said Friday. “It’s disappointing information about this officer, but putting all these facts together, we didn’t leave one stone unturned,” Smith said.

Smith said he could not say more about the relationship between Diaz and Smaller because of the pending case. It’s unclear when, where and how Diaz and Smaller crossed paths.

Smaller last attended Humboldt in 2007, St. Paul Schools spokeswoman Toya Stewart Downey said, and did not graduate from the district.

Cascarano, who represented Smaller in the attempted-murder case in Ramsey County District Court, said his client never mentioned Diaz or that he was receiving money in prison. Smaller was dating and living with another woman in St. Paul during his attempted murder case, Cascarano added. He was convicted in December and sentenced in January.

Charges: She wired $1,500

The Minnesota Department of Corrections requires people depositing money in inmates’ accounts to create an account with identifying information. According to the charges against Diaz, she sent Smaller $300 five times via Western Union between Feb. 2 and April 25 using the identity of a woman she had attended college with.

Diaz was also acting as a personal trainer for the woman.

The woman told police that she hadn’t spoken to Diaz as of late April, and that Diaz used her name, address and other identifying information.

Diaz also created a Google e-mail account with the woman’s name in order to create a profile in the Western Union database, the charges say. Diaz used three of her own credit cards to wire the money.

Diaz and Smaller had contact via phone and U.S. mail, according to the complaint.

Diaz’ mother, Irma Diaz, who lives in Chicago, said she wasn’t aware of the charges against her daughter and that she didn’t recognize Smaller’s name.

St. Paul Police Federation President David Titus said Friday that he hadn’t reviewed the complaint and couldn’t comment.

Diaz’s neighbor Don Vanderberg, a retired police officer, said she was quiet and kept to herself. “I think she’s an upstanding officer,” he said. “I have nothing but good vibes about her; positive feelings and positive impressions.”

Diaz’s record was clean

Diaz started with the department in 1999 as an intern and became a certified police officer in 2000. Her personnel file shows no disciplinary action against her.

Smaller’s family declined to address the new charges against him or the allegations against Diaz. His aunt, Rondria Smaller, said, “We’re just saying we love our nephew, our grandson and our cousin.”

Smaller is charged with firing into a house in October inhabited by two sisters, ages 72 and 69. Community leaders said that case was especially egregious among the three drive-by shootings because the women, longtime residents, were targeted to get back at one of their grandsons.

“It looked like a firing squad lined up and fired,” community activist and retired St. Paul police officer Melvin Carter Jr. said. “It was a level of devastation that was unspeakable.”

Authorities believe Smaller is affiliated with the Gotta Havit gang, which is a clique of the Selby Sider gang in St. Paul.