The last person believed to have seen Palo Alto resident Wamaitha Kaboga-Miller before she vanished on Aug. 17 said the 66-year-old woman was shaking and appeared to be too disabled to drive.

Kaboga-Miller left her Crescent Park home in her 2002 silver Mercedes-Benz CLK with California license plate number DP241LU at about 9:15 a.m. and drove to the Country Time Market at 2200 University Ave. in East Palo Alto, where she was seen purchasing cigarettes on surveillance video. Since that time, no one has seen her and she has not communicated with her family, according to one of her sons, Njoroge Kaboga-Miller.

Aziz Khalil, co-owner of Country Time Market, said on Tuesday that Kaboga-Miller was in the store for 15 to 20 minutes. She was shaking while she bought two packages of Marlboro Lights cigarettes. He said it was apparent that she was disabled -- so much so that he offered to help her get money or credit card out of her wallet.

"It took her 10 minutes trying to get the credit card or cash from her purse. I asked, 'Are you OK? Did you have a stroke?' She was not really looking healthy. I told her if she would trust me I would take out the credit card for her, and I charged her $21 for the cigarettes," he said.

Khalil said that Kaboga-Miller told him she had recently had back surgery. After making the purchase, she continued to remain at the counter, still unsteady and shaking. He did not think she should have been behind the wheel.

"When I got busy, I didn't see her when she left. I didn't know she was driving. If I did, I would have stopped her," he said.

A flyer of Kaboga-Miller being distributed by her family is tacked on the store's front door. Patrons entering the market in Tuesday asked if it was true that her car had been found. Khalil said he had heard that police had located the vehicle on Monday and towed it away, but had not located Kaboga-Miller.

Palo Alto police spokeswoman Janine De la Vega said officers have not found the car. Police had no further information to offer as of late Thursday morning. East Palo Alto police Cmdr. Jeff Liu also said his department had no information regarding the vehicle.

Meanwhile, Kaboga-Miller's family is baffled by her disappearance. Njoroge Kaboga-Miller said last week that she was afraid of the Dumbarton Bridge and was an infrequent driver. Family and friends held a search party last Saturday and were joined by many strangers seeking to find Kaboga-Miller or some trace of her or her car.

Flyers asking the public for information about Kaboga-Miller line the street trees in her Crescent Park neighborhood.

The family is considering holding a second search-party event, the missing woman's daughter-in-law, Sophia Kaboga-Miller, said on Tuesday.

"We got some leads from police and we are working to follow up on that information," she said. For now, the family is not making those leads public, she said.

Kaboga-Miller is described as a 5-foot, 1-inch tall black woman weighing about 120 pounds, according to the missing person flyer. Police said she was last seen wearing a black puffy vest over white long-sleeved shirt and light-colored pajama pants.

Anyone with information on her whereabouts is asked to call the Palo Alto Police Department's 24-hour dispatch center at 650-329-2413 or the family at 650-814-1189, or to email [email protected] Anonymous tips can be emailed to the police at [email protected] or sent by text message or voicemail to 650-383-8984.

This story will be updated as more information becomes available.