A woman who coached her children to fake mental retardation to collect disability benefits was sentenced to three years in prison Thursday.

Rosie Costello, 46, must also pay nearly $288,000 in restitution after pleading guilty in U.S. District Court to conspiracy to defraud the government and Social Security fraud. Last week, a judge sentenced her son, Pete Costello, to 13 months in prison.

The scheme was discovered after Pete Costello, now 28, was caught on surveillance video contesting a traffic ticket in a Vancouver, Wash., courtroom. Since he was 8, his mother had represented to state and federal officials that he was so severely retarded he could not perform simple tasks.

Earlier, she had used the same scheme with her daughter, Marie, beginning when the girl was 4. Investigators have been unable to find the daughter.

The sentence imposed was longer than the federal guideline.

U.S. District Judge Ronald B. Leighton called Costello a "habitual offender" who "asked her children to do despicable things," according to a statement from the U.S. attorney's office in Seattle.

"I'm sorry for what I did," Costello told the court. "I had a very hard life. I have grandchildren out there who need me. If I could, I would take it all back."