A U.S. Marine was taken from his wife and newborn child on Saturday night because Cape and Islands District Attorney Michael O'Keefe's office made a mistake. Oopsie!

Thirty-two-year-old Kevin Quinn of Mashpee was killed when his SUV was struck head-on by a car being operated by 22-year-old Mickey Rivera of Fall River. Police say they spotted Rivera's car operating erratically on Route 28 in Barnstable, and when they attempted to stop the vehicle, it sped off. Rivera was also killed in the crash.

Courtesy Bristol County DA's Office

Rivera, with a rap sheet that connects him to a Fall River murder, a pair of stabbings in Taunton, and an armed home invasion while masked, was released on $1,000 bail last September and was wearing a GPS monitoring device. Court documents show Rivera had considerable involvement with the court system, both as a juvenile and an adult. He was due to appear in court on Wednesday for a pretrial conference on charges related to the armed home invasion.

What makes all of this even more tragic, if that is possible, is that Rivera was arrested for drunk driving in Hyannis earlier this year. That's an offense that should have resulted in Rivera's bail being revoked and his immediate incarceration. But that didn't happen because someone made a mistake.

D.A. O'Keefe tells the Boston Globe the as yet unnamed assistant district attorney that handled River's arraignment on the drunk driving charge had only been on the job for a month, and neglected to ask to have Rivera's bail revoked. Whoops! That means Rivera was free to walk out of the courtroom, GPS monitoring device and all.

Had the Cape and Islands D.A.'s Office done its job, there is a real good chance that Quinn, who survived two tours in Afghanistan, would be alive today and at home with his wife and new baby. But somebody made a mistake.

A mistake, to my way of thinking, is forgetting to invite Aunt Sally to the family clambake or leaving the milk on the counter all night. Neglecting to ask a judge to revoke the bail of a violent criminal who gets busted for drunk driving is negligence. Especially when someone dies as a result of that action.

D.A. O'Keefe must identify who the assistant was who made such an egregious error. That person and O'Keefe must be held accountable for what happened on Saturday night. Why was a case involving such a notorious defendant given to an assistant district attorney with only one month's experience anyway? Why wasn't O'Keefe supervising such an inexperienced underling on such an important case?

People are dead because an inexperienced prosecutor made a mistake. The buck stops on O'Keefe's desk.

Barry Richard is the host of The Barry Richard Show on 1420 WBSM New Bedford. He can be heard weekdays from noon to 3 p.m. Contact him at barry@wbsm.com and follow him on Twitter @BarryJRichard58. The opinions expressed in this commentary are solely those of the author.