A pair of roommates who stole a check from a Newport Beach law firm were convicted and sentenced to three years of formal probation and 305 days in jail Thursday, authorities said.

Alexa Antonella Polar, 35, and Robin Johzen Pabello, 34, lived together in Garden Grove in 2011 when they stole a $19,500 check and changed the amount to more than $285,000, according to the Orange County district attorney's office.

The women used the money to charter a private jet to fly them and several friends to New York, pay for five hotel rooms near Times Square, and go on a spending spree at Tiffany & Co. and Montblanc, prosecutors said.

The check was addressed to a Newport Beach law firm, where Polar worked as a paralegal at the time of the theft, prosecutors said.

Polar and Pabello also used fraudulently obtained cashier's checks to buy a 11,000-square-foot house in Murrieta, according to the D.A.'s office.

The women were discovered after the bank that issued the check rejected it, prosecutors said.

The women paid restitution in full, and will receive credit for time served, according to the D.A.'s office.

Polar pleaded guilty to one felony count of forgery and Pabello pleaded guilty to two felony counts of forgery with a sentencing enhancement for committing a white-collar crime over $100,000.

Both women remain in custody, according to Orange County Sheriff's Department records.

— Lauren Williams

Twitter: @lawilliams30