But with only a single photograph she knows she can't be sure.

"When my husband sat down and showed me the photo, I was relieved," she says. "But at the same time, I was very upset and my heart was broken when I saw my son looking like that. It was humiliating."

Both the al Drimli and the al Madoun family say neither they nor their sons have any affiliation with Hamas or any of the militant groups in Gaza.

The BBC asked the IPS about both men. They said they had no record of holding either of them.

We put the same question to the Israeli military which also runs detention centres and prisons, but it did not give a response.

Israel does not allow international journalists, including the BBC, independent access to Gaza.

The Al Drimli family has asked the Red Cross to try to find out if Mahmoud has been detained. But Israel does not allow the Red Cross access to its prison records.

Tal Steiner, an Israeli lawyer who works to locate Palestinians who may have been detained by Israel, told the BBC "Oct 7th changed everything".

"The ban on the International Red Cross [visiting prisons] and the fact that the ICRC itself holds no lists of people held by Israel means we have to trace them individually one by one, per request by their families. It's a big strain on the ability to find those people, today."

She also says for the families, it's the not knowing that is the hardest.

"It's an open wound. It doesn't heal. They have no rest not even knowing if their relative is dead or alive," she tells us.

And she says over the last three years Israel has made it much more difficult to trace possible Palestinian detainees.

"To those not knowing where their family members are, that really adds insult to injury. It's a very difficult mental situation that can be carried for months and years."