Forty days ago today was the last time Laina McMahon saw her mother Sandra Crispo before she vanished without a trace.

“40 days ago.... If I knew it was the last time I would talk to you, I would’ve talked longer,” Laina wrote on her Facebook page. “If I knew it was the last time I would see you, I would’ve told you I love you.”

Sandra, 54, moved to a house on Spofford Avenue in Hanson, Massachusetts from Quincy, Massachusetts only three months ago to be closer to her grandchildren. She takes care of Laina’s three young boys while Laina works long hours as a nurse in Boston.

“If knew it was the last time my children would see you, I would’ve had them hug you longer,” Laina’s Facebook post continued. “Sometimes life doesn’t seem fair. Sometimes bad things happen to innocent people. Not knowing how, why or what happened to you is devastating.”

Laina told Dateline her mother was last seen on Wednesday, August 7. Laina had dropped her sons off with Sandra in the morning as usual before heading off for work. Laina said her mother later discovered she was having mechanical issues with her vehicle.

Since Laina was still in Boston, another family member picked up Sandra and the boys and drove Sandra to drop off the vehicle at a mechanic shop. Security footage shows Sandra getting out of the car and going into a Cumberland Farms to buy cigarettes, after which she was taken home.

“That’s it. That’s all she does,” Laina said of her mother. “She’s a homebody. Doesn’t go out much. She doesn’t have a lot of friends. She lives a very quiet life.”

On Thursday, Laina’s mechanic, who checked out her mother’s car, called Laina to discuss needing more parts. Laina had that day off and was enjoying the beach with her children. She called her mother to tell her the news about the car.

“When she didn’t pick up the phone, I was instantly worried,” Laina said. “She didn’t have a car, obviously, and she doesn’t really go anywhere. Why wouldn’t she answer the phone?”

Laina called her mother a few more times that day, but her mother never picked up.

Sandra was supposed to watch Laina’s children Friday, so when Friday morning rolled around, she drove over to the house.

“Something felt different -- felt wrong,” Laina said. “Usually when we pull in the driveway, I tell the boys, ‘OK, everyone unbuckle,’ but not this time.”

Laina told Dateline she got out of the car and went to the house, but her mother didn’t come to the door. She peered inside the windows. All the lights were on. But no sign of Sandra.

Laina said she discovered the back door was unlocked. Once inside, she noticed her mother’s shoes and purse were gone. The air conditioning and lights had been left on. Inside the refrigerator, there was watermelon already cut up and ready for the boys to eat.

“She knew she was supposed to watch them that day. She would have never just left,” Laina said. “She loved having them here.”

Sandra’s dog was perched quietly in the recliner. But the dog was out of food and water.

“Something was very wrong,” Laina said. “That dog, her dog, is usually jumping all over the place. Not this time.”

Laina reported her mother missing and an investigation was launched by the Hanson Police Department.

“We have no idea where Sandra is,” Hanson Police Chief Michael Miksch told Dateline. “Someone disappearing is suspicious in and of itself, but there are no signs of foul play, nothing out of the ordinary at her house. We just don’t know.”

Laina told Dateline her mother does not have a cellphone or a computer, which police say makes it harder to locate someone, as there is no digital trail.

Police took to Facebook to ask for the public’s help and have released several photos of Sandra in the hope that someone would remember seeing her.

Miksch said the department has searched multiple places in the area and have followed up on countless leads and tips. Nothing has led to Sandra.

“Honestly, I’m baffled,” Miksch said. “But we haven’t given up. We’re going to keep looking.”

Laina told Dateline she believes someone in the neighborhood, at the very least, saw something.

“My gut is telling me something bad happened. Someone did this to her,” Laina said. “She would never just leave her grandchildren, her dog, her life.”

She said her mother was not suicidal, was not on any medications and had no serious medical problems.

“It doesn’t make any sense. She’s not the kind of person who would just leave,” Laina said. “It’s mind-boggling to everyone, even the police. But I just know that I’m going to do everything I can to get her back.”

The Hanson Police Department has no reason to believe any foul play is involved, but are actively investigating.

Sandra is described as a 5-foot-9 white female with hazel eyes and brown hair.

If anyone sees someone matching Sandra’s description or has any information on her whereabouts, they are urged to contact the Hanson Police Department at 781-293-4625.