Thousands of Palestinians in Gaza are looking for their relatives who have gone missing in one of the most destructive wars of the past decades.

Some are buried under the vast ruins of destroyed buildings. Others, simply disappeared during Israeli military operations.

Some 6,000 people have been reported by relatives to still be buried under rubble, according to the Health Ministry.

The true number is likely thousands higher because in some cases entire families were killed in a single bombing, leaving no one to report the missing, said Zaher al-Wahidi, the ministry official in charge of data.

Separately, the ministry has reports from families of some 3,600 others missing, al-Wahidi said. So far, it has investigated around 220 cases.

Seven were found detained by Israel. The others were not among those known to be dead or buried under rubble.

The International Committee of the Red Cross (ICRC) has its own separate list of missing — at least 7,000 cases still unresolved, said chief spokesperson Christian Cardon.

There have been many ways to disappear during the chaos of offensives, building destructions and mass displacements of almost all of Gaza's 2.3 million people.

Hundreds have been detained at Israeli checkpoints or were rounded up in raids with no notification to their families.

During Israeli ground assaults, bodies have been left in the streets. Palestinians have been shot when they came too close to Israeli military zones, their bodies inaccessible. Some are found weeks or months later, decomposed.

The Israeli military has taken an unknown number of bodies, saying it is searching for Israeli hostages or Palestinians it identifies as militants. It has returned several hundred corpses with no identification to Gaza, where they were buried in anonymous mass graves.

Investigating the missing needs advanced DNA technology, DNA samples from families and unidentified bodies, aerial imagery to locate burial sites and mass graves, said Bomberger.

Israel has restricted DNA-testing supplies from entering Gaza since before the war, according to Bomberger and the Gaza Health Ministry.

Israeli military authorities would not comment when asked if they were banned.

Fadwa al-Ghalban has had no word about her 27-year-old son Mosaab since July, when he went to check on the family house in the southern town of Maan.

His cousins saw Mosaab near the house when an Israeli strike hit, destroying it.

From a distance, they saw him on the ground. They shouted his name, but he didn’t answer, until they had to leave to escape bombardment.

Returning later, family members found no body, only his slippers.

Her family has put up notices on social media, hoping someone saw Mosaab in Israeli detention or buried him after finding his body.

All al-Ghalban has left of her son is his last change of clothes. She refuses to wash them.