Jaber Al Suwaidi had known Bulos "Paul" Zumot and Jennifer Schipsi for more than two years and had exchanged hundreds of text messages with both.

So when he received a message from Schipsi's phone on the afternoon of Oct. 15, 2009, saying that Zumot wasn't mad at him for missing his birthday the previous night, he suspected it wasn't Schipsi who wrote it.

"It's not her writing," Al Suwaidi testified Monday afternoon at Zumot's arson and murder trial.

After further questioning by prosecutor Charles Gillingham, he elaborated:

"I thought it was Paul. I thought he wanted to become friends again."

Al Suwaidi's testimony rankled Zumot's attorney, Mark Geragos, who pounced on Al Suwaidi's assertion that he could recognize the authors through the messages. Al Suwaidi, a student at Menlo College, said Schipsi's messages tend to be less formal than Zumot's and that she frequently uses popular abbreviations such as "LOL" (for "laugh out loud").

Geragos pointed to examples of Zumot's text messages that had abbreviations, including a message Zumot had reportedly sent Al Suwaidi on the night of Oct. 14, after Al Suwaidi didn't show up at his birthday party or call to wish him a happy birthday. After Al Suwaidi responded to tell Zumot that he wants to wish him a happy birthday in person, Zumot wrote back, "It's ok. This is who U R. Good luck to U."

Police believe Zumot had killed Schipsi the following afternoon and then set fire to the cottage shortly after 6:30 p.m. to hide the crime. Earlier in the trial, Gillingham pointed to records from cell towers suggesting that Zumot had Schipsi's cell phone in his possession as he drove from San Jose to Palo Alto that evening.

But Geragos said Zumot was at his place of business, Da Hookah Spot, when the fire began and he didn't get to the cottage until later. He repeatedly disputed Al Suwaidi's professed ability to determine the author through grammar and pointed to earlier messages from Schipsi to Al Suwaidi where abbreviations are scarce, including one in which Schipsi wrote, "Paul asked me to pick up a CD."

"Let me guess, 'CD' is abbreviated, so it must be her," Geragos said.

Al Suwaidi acknowledged that the person sending the Oct. 15 message from Schipsi's phone could've been anyone, but said that in his opinion it was Zumot. He testified that he thought Zumot is trying to make up for the rancor of the previous night.

"They're different," Al Suwaidi said. "If you have them as friends, you know."

Al Suwaidi also testified that Schipsi called him on the night of Oct. 14, 2009, just after she had argued with Zumot on the drive back to Palo Alto from Zumot's birthday party in Sunnyvale. They arrived at Da Hookah Spot after which time she walked back to the cottage she shared with Zumot on Addison Avenue. Her body was found in the cottage the following evening by firefighters responding to a cottage fire.

Al Suwaidi said Schipsi was breathing heavily and crying as she walked home alone from the hookah lounge. She also told Al Suwaidi that Zumot had "humiliated her" so she left.

"She was crying and she said she's done and that she can't handle it anymore," Al Suwaidi testified. "She was hysterical."

The jury also heard on Monday from John Eckland, who owns the cottage where Zumot and Schipsi had lived. Eckland, who lives in a house at the back of the property, testified that he was preparing to have dinner with his father and a few friends when someone knocked on their door and told them about the fire.

Eckland and a guest, Eden Salomon (who also testified Wednesday), then ran out to the cottage and dowsed the flames before firefighters arrived.

Eckland also testified that earlier in the day he had noticed a bracelet lying on the ground, near the cottage. He said he picked up the bracelet, put it in a Ziplock and called Zumot at the hookah lounge about 3 p.m. to tell him he has the bracelet. Later that evening, he called Zumot again to tell him the cottage is on fire.

"I can hear the receiver hit the floor and he was on his way over," Eckland said.

The trial will resume Tuesday morning.