Four days after her disappearance alarmed family and friends and triggered a citywide search, Miami police found an 86-year-old retired crossing guard shopping for snacks at a Publix supermarket in Coral Gables.

Alice Martell’s grandson first called police Monday evening after they argued and she walked out of her house.

“I just thought, she knows I would never be OK with her leaving in the evening,” said Brandon Calderin, who lives with his grandmother in the 100 block of Southwest 40th Avenue. “But she does her own thing.”

Calderin said he began searching for Martell at all her favorite haunts: the Walgreen’s on Coral Way and a nearby Winn Dixie. Martell typically rides the bus or walks, but keeps a regular routine, attending meetings every Thursday with her seniors’ group at the First United Methodist Church of Coral Gables, and every Sunday at University Baptist, he said.

Until last year, she had been the crossing guard at Coral Gables Elementary school for more than a decade, an orange-gloved fixture at the crosswalk on busy Ponce de Leon Boulevard every morning and afternoon, rarely missing a day. And when she announced her retirement, students wrote her poems.

Martell had moved to Miami from Illinois in the 1950s with her husband, and raised two adopted children, including Calderin’s mom, he said. When her husband became ill, Martell worked two jobs to support the family.

“She’s so tough. She makes me look bad,” he said. “She’s so selfless and she never talks about anything that’s hurting her.”

After she retired last year, she busied herself with her church activities, shopping and doctor’s appointments, Calderin said. Friends described her as fiercely independent and reliable.

So when she failed to come home, they grew alarmed and joined police in handing out fliers, posting them at City Hall in Coral Gables, Gables Elementary and the nearby Publix. At least one local TV station aired a story on her disappearance.

“She would not go anyplace without knowing where she was going,” said Dottie Drennan, who organizes the seniors’ group at the Methodist church. Martell is the group’s lunch treasurer, Drennan said, and would never shirk her duties.

Sure enough, on Friday just before lunch, two employees from her doctor’s office spotted her buying snacks for Sunday’s church group.

“They said, ‘Uh, do you know you’re missing?’ ” said Miami Detective Maykel Baluja. “So they told the manager at Publix, and said this lady’s a client and she’s been missing and it’s been on the news. And they brought a flier they had at the store.”

When Baluja arrived and questioned Martell, she matter-of-factly told him she was angry at her grandson and so she left.

She told him she got on the bus, but couldn’t or wouldn’t say where she spent Monday night. Then she booked a room at the Coral Gables Extended Stay hotel on Tuesday and Wednesday, where rooms cost about $180 a night. She kept a doctor’s appointment Wednesday in Coral Gables, but checked out of the hotel about 11:30 a.m. Thursday and headed to Miami International Airport, Baluja said, where she stayed until she remembered her obligation to provide snacks for Sunday’s meeting, so headed to the store Friday.

When Baluja asked why she failed to answer her cell phone, she explained the battery died and she forgot her charger.

“She’s very independent, so thankfully she’s OK,” said Baluja, who also questioned her grandson and examined her home to make sure there were no signs of abuse or neglect. “But we advised her that she can’t be doing this because we had the whole city looking for her. And the media. We said because she’s 86, it’s not normal to leave the house for five days and not tell anyone.”

Reached after she was found, Calderin was breathless.

“Oh my gosh. I’m still trying to get to the bottom of it,” he said. “I’m just here now with the police trying to figure it out.”