Published: Jan 27, 2011 10:58 PM EST
Updated: Jan 27, 2011 8:01 PM EST

SAN RAFAEL, Calif. (AP) - A search was under way Thursday for a Northern California teacher who went missing after leaving a mysterious message on her classroom blackboard.

Students of Debra Schmitt told San Rafael police they found the message "Thank you everyone" but not their teacher when they showed up for her English class at Terra Linda High School on Jan. 20.

Schmitt, 53, was last seen a day earlier in Ross, where she lives.

Police said there were no indications Schmitt had been kidnapped or attacked, and authorities found her car, identification and purse at her home.

Schmitt's cousin Linda Czarnik said the teacher, who has a son in eighth grade, was going through a divorce and had lost three close relatives in the past year, though it was unclear if those events were connected to her disappearance.

"We know it's been a sad time in our family," Czarnik told the San Francisco Chronicle. "It's a heavy burden - on all of us - but for her to hurt herself? I just can't see it."

Authorities searched the Phoenix Lake area near Ross and Golden Gate Park in San Francisco, which Schmitt told a friend she wanted to explore.

Public records showed that Schmitt's husband, Stephen Smith, filed for divorce in Marin County Superior Court on Jan. 11.

Czarnik, who last exchanged e-mails with Schmitt on Jan. 19, said her cousin is "a very strong person, physically and emotionally."

"She was always warm in her words, her conversation, her attitude, at least with me," Czarnik told the newspaper.

(Copyright 2011 by The Associated Press. All Rights Reserved.)