Reward Raised for Clues to Millionaire’s Slaying : Investigation: Also, the victim’s girlfriend attends a hearing on charges that she forged checks in his name.

The family of millionaire William F. McLaughlin, who was found shot to death in his Balboa Cove home, offered a $100,000 reward Tuesday for information about the unsolved murder.

Family members had previously offered a $40,000 reward, and they said they more than doubled the amount to focus renewed attention on the Dec. 15 slaying.

“We are hoping that someone will come forward that has information that would lead to the arrest and conviction of whoever killed my father,” Jenny McLaughlin, 26, said Tuesday during a press conference at the Newport Beach Police Department.

The new reward was announced on the same day that McLaughlin’s girlfriend, Nanette Anne Johnston, appeared at a preliminary hearing to face allegations that she stole nearly $500,000 from McLaughlin by forging checks in his name shortly before he was shot to death in the home they shared.

Newport Beach Police detectives have identified Johnston, 29, and another boyfriend, former professional football player Erik Naposki, as “possible suspects” in the killing, but said the investigation is continuing.

“We are trying to improve our case and our leads,” Newport Beach Police Sgt. Andy Gonis said. “In many ways we are at a standstill.”

Johnston and Naposki have denied any role in McLaughlin’s death.

The 55-year-old entrepreneur died of six gunshot wounds to the chest. His son, Kevin, found the body.

Police investigators first named Johnston and Naposki, 28, as possible suspects in February after they determined that Johnston stood to gain $1 million in insurance proceeds and discovered her romance with Naposki.

During Tuesday’s court hearing, Johnston sat without expression as an accountant who helped manage McLaughlin’s finances described later finding a string of checks--including one for $250,000 dated the day before his death--that bore McLaughlin’s name but an unfamiliar script.

Deputy Dist. Atty. Joe D’Agostino said that checks worth $267,000 were written to Johnston from an account over which McLaughlin had sole control. At least $130,000 more was moved from the McLaughlin account in the days before his death to a separate account from which Johnston was empowered to write checks, accountant Brian Ringler testified.

The checks bearing McLaughlin’s name were dated before his death, but some did not clear the banks until weeks after the Dec. 15 murder, Ringler said. “I know banks are slow, but I wouldn’t expect them to be that slow,” Ringler said.

Defense attorney Barry Bernstein suggested that Johnston was allowed to sign McLaughlin’s name on checks and other documents when he was unavailable.

McLaughlin’s daughter Kim, 28, wept as Ringler testified in Municipal Court in Newport Beach. She attended the hearing with her sister, Jenny.

At the press conference earlier in the afternoon, Jenny McLaughlin said that the family has had no contact with Johnston since shortly after the slaying.

McLaughlin and Johnson had owned a weekend home together and shared some bank accounts.

“I don’t believe my father had any intention to marry her. He certainly didn’t share that with me,” Jenny McLaughlin said.

Johnston’s preliminary hearing resumes today in Newport Beach. At its close, Municipal Judge Richard F. Toohey will decide whether there is enough evidence to warrant a trial for Johnston on the forgery and grand theft charges.

Police asked that anyone with information about the McLaughlin slaying call (800) 550-NBPD.