Cody Hall's attorney had asked for a bail of $150,000, but the prosecution argued that the threat existed based on a history of speeding. In one case, Hall was cited by police after being clocked at 70 mph on Foothill Road, the same place the fatal crash occurred, according to assistant District Attorney Sharon Carney.
"He also had been in a collision in August, 2011," Carney told Alameda County Superior Court Judge Jacob Blea III. "He was fully aware of the speed limit."
Carney said in that crash, Hall rear-ended another vehicle as it neared Foothill High School. The prosecutor also cited three instances in which Hall, who turned 19 while in custody, posted on social media accounts, including one in which he claimed to be driving 140 mph on Interstate 5 and said, "I can't control myself."
In another post, Hall said he was driving 100 mph on W. Las Positas Boulevard, Carney added.
In addition, Carney noted that the investigation had turned up two vehicles that were totaled but were not reported to police.
Hall was originally arrested for vehicular manslaughter with gross negligence and reckless driving with serious injury following the June 9 crash that killed bicyclist Diana Hersevoort, 58, of Dublin and left her husband, another rider, with a broken leg.
Carney told the court that Hall had crossed a double-yellow line to pass two cars, both times causing oncoming traffic to slow down.
In the second incident, court documents show, Hall was traveling 83 mph, more than twice the speed limit, when he lost control while pulling back into his lane, where he fatally struck Hersevoort and her husband before hitting a pole.
Charges against Hall were upgraded to murder in August. At an initial hearing, Judge Hugh Walker said Hall had "dug a hole so deep, I don't think he can get out of it," and ordered that he be held without bail.
Defense attorney Timothy Rein attempted to have the bail lowered, claiming that the evidence was available when the initial charges were filed, when Hall was released on a $100,000 bond. Rein also said a no-bail hold only applied in specific cases.
"This is not a capital case," Rein told the court. "It would appear that bail would be permissible."
In making his ruling Thursday, Blea said "the persuasive evidence of speed" qualified Hall as a threat.
Hall entered a plea of not guilty to all counts. He's set for a preliminary hearing on Feb. 5.
Hersevoort's two daughters were at the bail hearing Thursday morning in Pleasanton, but declined to comment. About a half dozen of Hall's friends and family members also attended the hearing.