(NewsNation) — Just over five months ago, Maria del Carmen Lopez was kidnapped from her home in Pueblo Nuevo, Colima, Mexico. Her family has not heard from her captors in months, but are holding onto hope they’ll see her again.

The 63-year-old U.S.-Mexico dual citizen relocated to Mexico 10 years ago, but as a mother of seven and grandmother of 19, she frequently returned to Southern California for medical appointments and to visit her family.

Her daughter, Zonia Lopez, told NewsNation she believes it was a targeted attack, saying her captors have reached out to her California family asking for ransom.

The family received a phone call from Mexico on February 9, the day Maria was abducted.

“Your mind goes into fight mode,” Zonia said. “Your body, it’s a complete shock.”

Zonia said her mother’s neighbors called, telling her they saw Maria get kidnapped. Immediately, their family began calling the authorities to report her abduction.

“We didn’t know what to do. What do you do in this instance?” Zonia said.

Since Maria is also a U.S. citizen, her family questioned who they were supposed to ask for help from. Do they call American agencies, or try to get help from Mexico? Zonia said she didn’t know what to do but called the local authorities near her for guidance.

But the details about her mother’s kidnapping were sparse and difficult to hear.

“It was very limited at the beginning,” she said. “There were three to four men who came in a van, and they took her. They drove all the way inside (the property).”

Zonia explained that her mother was watering her plants outside in her garden when a van drove inside the property and down the very long driveway to where she was. Two men wearing hoods jumped out of the van, and there was reportedly some type of exchange of words before a third heavy-set man came out to assist in taking Maria. A fourth man covered her mouth before they picked her up, put her in the van and drove off.

“That was it,” Zonia said. “That’s all we had.”

A day after Maria’s abduction, her family received a phone call from an individual who told them he had their mom. Zonia said the kidnapper told them they had to do everything they said and pay a hefty, six-figure ransom.

“We all knew we were in trouble because we don’t have that kind of money,” Zonia said. “We did ask for proof of life, and within 48 hours, there was a recording of my mother, pleading for her life.”

Then the abductors hung up.

“It was just a nightmare,” Zonia said.

The same day, the FBI jumped on the case.

“There is photographic video evidence, not necessarily of the kidnapping per se, but around her residence, whenever males were seen talking to her as well as then returning to the house before she was taken,” FBI Los Angeles Assistant Director Donald Alway said. “We’re now working closely with Mexican authorities.”

A $20,000 reward was originally offered for any details that lead to Maria’s safe return.

The family is also seeking help from President Joe Biden and Mexican President Andres Manuel Lopez Obrador.

“We’ve reached out and we were pleading to the president to please deploy our resources. Although the FBI is on the case, we still need answers and we don’t have our mother,” Zonia Lopez said.

Despite the kidnappers’ ransom demand that Maria’s family is unable to fulfill, they continue to hold onto hope as the passing weeks have turned into months, but their faith keeps them strong.

“She’s a US citizen. Everyone in the town is born there — raised,” Zonia Lopez said. “I think this was a targeted attack with the thinking or the knowledge that she has her family here in the United States and that we might have money.”

Since the proof-of-life call, the calls stopped and it’s been silent for the past five and a half months.

“It’s excruciating pain because you don’t know if your mother is gonna be safe. You don’t know if this is the last time you’re gonna hear her, or if it’s gonna be the last phone call that they’re gonna be making, and you just don’t know,” Zonia said.

Zonia Lopez said she believes the FBI and Mexican authorities were able to trace the location of the phone calls; however, they’ve received limited updates on the investigation.

The FBI insists it is working on the case with Mexican authorities.

“It’s absolutely fresh and active,” Alway said.

The reward for information has since been updated to $25,000 and added two images on the bulletin showing the handguns the men were carrying.

“We know that those photographs were from a proof-of-life video that was provided to the family from the kidnappers,” Alway said. “We’re always hopeful. We work these cases until we can’t anymore. So we are hopeful that we will identify and have her return home.”

But her family is exasperated at what they feel is a slow investigation and has asked Biden to intervene.

Zonia and her family have a message to their mother’s captors:

“She’s a mother. She belongs with us. We’re not a rich family. We don’t have what you’re asking for. Please find it in your heart to just give her that. It’s been five months of absolute help for us. Please contact us. We need her.”

And to their mother, directly:

“Mom, I’m sorry. You’re very strong. It’s been over five months, and we have not stopped a single day. We are doing everything that we possibly can to find you, and we’re not gonna give up on you, mom. We love you and your grandchildren and all of us, your kids. We all miss you. And we’re looking for you, mom. Please hang on. We’re going to find you.”