MARTINEZ, Calif. -- Family members of a San Ramon man who investigators believe was murdered Sunday because of an alleged real estate fraud scheme confronted the suspect's attorney outside a Martinez courtroom Thursday.

The suspect, El Sobrante resident Reginald Robinson, 31, had just been arraigned on charges of murder, solicitation of murder and being a felon in possession of a firearm in connection with the fatal shooting Sunday night of 42-year-old Kashmir Billon.

Although police initially said they believed Robinson had hired someone to kill Billon, his business partner, they said Thursday that they now have evidence suggesting Robinson may have pulled the trigger himself, fatally shooting Billon in the chest.

Firefighters found Billon's body at about 11 p.m. Sunday near a smoldering car at 2600 Bishop Drive in San Ramon.

Robinson did not enter a plea during his arraignment Thursday. He is scheduled to appear in court in Martinez May 8 for further arraignment.

"It's a tragedy on both sides," Oakland-based defense attorney Adante Pointer was telling reporters outside the courtroom when the victim's brother interrupted him.

"Did you ask him why he did it?" Harv Billon asked.

Pointer said he didn't ask Robinson why he did it and said that Robinson had said he did not kill Billon.

Harv Billon said evidence would come out that would prove Robinson killed his brother.

"Trust me - he will hang. [He] will die," Harv Billon said as his cousin held onto him, gently pushing him back from the attorney.

A few minutes later, Harv Billon told reporters that his brother had known Robinson for many years, had been a mentor to him and had even helped him buy his house.

"Kas took him in," Harv Billon said.

He said Robinson "took advantage of his (brother's) innocence."

Harv Billon described his brother as a person who was always helping people.

"Our families are grieving the loss of a really good man," Harv Billon said. "He was a really good man in the prime of his life. We want justice."

Earlier Thursday, Supervising Deputy District Attorney Harold Jewett said that Robinson had allegedly killed Billon over a real estate fraud involving a piece of property on Seventh Street in North Richmond.

Billon reportedly financed the purchase and construction of homes on property that Robinson owned. Although details of how the fraudulent transaction was allegedly supposed to work were not released today, it appears that Robinson planned to sell those homes to a fictitious person through a bank.

The fraudulent purchase was reportedly scheduled to close escrow Monday, "leaving the bank holding the bag," Jewett said.

Investigators are still working to determine how much Billon knew about the alleged scheme.

"It's possible he was killed because he found out about the fraud," Jewett said.

San Ramon police got a break in the case shortly after the murder when a person officials are not identifying contacted investigators and told them that Robinson had allegedly solicited that person to kill Billon the Friday before the murder, Jewett said.

The person said no, and after learning of Billon's murder, contacted investigators and told them about the alleged earlier solicitation, Jewett said.

Robinson was arrested at his El Sobrante home Monday night.