Jacqueline Toves, 26, and Abigail Tapia, 27, had lived together as a couple in Long Beach and were found dead in a cabin Friday at the Gorda Springs Inn in the rugged Big Sur region.
Their hands were bound with duct tape and one of the black bags had a grinning Halloween mask attached to it, the Monterey County Sheriff's Department said.
Toves' father, Francis Toves of Agat, Guam, said his daughter had tried to kill herself about two years ago.
"I know she had a problem before, she tried to take her life with pills," he told the San Jose Mercury News. "But she went to a psychiatrist, and I thought she was doing pretty good."
Authorities said autopsies were scheduled for Monday. They would not release other information.
On Monday, a frowning, green-and-red mask hung on the door of the women's Long Beach apartment, just blocks from the beach. All the shades were drawn.
Dan Kaplan, 29, a next-door neighbor, said the women were friendly and appeared inseparable. "Every time I saw one, I saw the other," he said.
The owner of the Big Sur inn, Sherwin Miller, called the deaths "a very sad event."
Set on a cliff overlooking the ocean and charging $200 to $500 a night, the hotel usually attracts a mix of hikers, cyclists, celebrities and honeymooners.
The women checked in on Oct. 3, Miller said. They were in a $220-a-night oceanview cabin with a fireplace and porch. A neighbor staying in the cottage next door complained of loud pounding coming from the room the first night.
The women had declined housekeeping service, said Leonardo Flores, the employee who discovered the bodies after the guests failed to check out.
Some residents worried that the deaths were the result of an attack.
"I'm thinking we might have a weird person around here," said Kathleen Millsap, a manager at the nearby Lucia Lodge.