An attorney and former San Ramon resident who killed a bicyclist in a hit-and-run collision in Dublin in 2012 could face up to a year in county jail after a judge Thursday placed him back on felony probation, saying the attorney failed to live up to the terms of his probation and an agreement with the court by testing positive for cocaine.

Alameda County Superior Court Judge Michael Gaffey said he tried to give 36-year-old Spencer Freeman Smith "an opportunity" last Oct. 12 by reducing his felony hit-and-run conviction to a misdemeanor for striking and killing 57-year-old Bo Hu on Dougherty and Fall Creek roads in Dublin on May 15, 2012.

In addition, Gaffey agreed in October to reduce the sentence for Smith, who also had pleaded no contest to misdemeanor vehicular manslaughter, from five years of felony probation to three years of misdemeanor probation.

Gaffey said Thursday, "This was a plea bargain between the court and Mr. Smith and he has not abided by it."

The judge on Thursday ordered Smith, who lived in San Ramon at the time and practiced law in San Francisco, to serve a year in the county jail as a result of the change back to felony probation.

Smith was arrested two days after the fatal collision when Dublin police identified him as the owner of a recently purchased black 2012 Mercedes-Benz CLS550 connected with the collision.

Dublin police said Smith's car sustained extensive windshield and front-end damage and was missing parts that were recovered at the scene of the collision.

Gaffey could have sentenced Smith to up to three years and four months in state prison, but at a hearing last Sept. 25 he chose not to send him to prison and instead placed him on the felony probation. He then reduced the sentence to misdemeanor probation at the Oct. 12 hearing.

However, according to court records, Smith tested positive for cocaine on Oct. 29 after he returned from a trip to Dubai with his pregnant wife.

He was arrested on Jan. 27 and was placed in Santa Rita Jail in Dublin after he failed to appear for a previous hearing for his probation violation.

Smith's attorney, Rebecca Feigelson, said Thursday that Smith only had "trace amounts" of cocaine in his system and argued that his sentence shouldn't be changed.

Feigelson said Smith has no prior criminal record and "it could be a complete accident" that Smith collided with Hu after a night of drinking and left the scene of the collision.

But prosecutor Matt Gaidos argued that Smith should be placed on felony probation, saying that Gaffey "gave Mr. Smith every benefit of the doubt that he was deserving of the court's leniency and that hasn't been earned."

Gaidos also said that when Smith returns to court on Feb. 25, Gaffey should consider sending Smith to state prison because he believes Smith deceived the judge about his wife's health at the Oct. 12 hearing.

Gaidos said Smith asked not to serve any time in jail in October because his wife was in delicate health because of her pregnancy and she needed bed rest.

But Gaidos said Smith and his wife then traveled to Dubai for a vacation one week later and failed to notify his probation officer, even though he wasn't supposed to travel outside of California.

Feigelson said Smith doesn't deny that he and his wife traveled to Dubai but she said Smith didn't misrepresent his wife's health condition.

The question of whether Smith deceived the court will be addressed at his Feb. 25 hearing.

After Thursday's hearing, Feigelson said she doesn't think the judge has the legal authority to increase Smith's sentence.