More: Several hundred Palestinians have been detained on suspicion of direct involvement, and at least 200 of them remain in custody, according to public records. Israeli military officials have said that at least several dozen Palestinians were arrested in or near Israeli territory around the time of the attack on Oct. 7, 2023.

In addition to those detainees, Israel is holding roughly 2,700 other Palestinians who were rounded up in the Gaza Strip over the 21 months since the attack, according to government data. They are suspected of affiliation with Hamas or other militant groups in Gaza, but not necessarily of direct involvement in the Oct. 7 attack.

Israel has killed many of the senior Hamas figures from Gaza who were seen as masterminds of the attack. But some in the country worry that the extensive delays in prosecuting the suspects in custody will allow some perpetrators to escape justice.

Palestinians and rights groups have other concerns.

They say Israel has systematically violated the detainees' rights by holding them without charge or trial in harsh conditions, with limited access to legal counsel. Sweeping gag orders keep most details of their cases under wraps and for most of these detainees, there is no trace of them in any public records.

The way Israel detains those prisoners "effectively erases these individuals from public awareness and strips them of fundamental rights," said Nadine Abu Arafeh, a lawyer who has represented detainees from Gaza in other cases in Israeli courts. "Families in Gaza live with questions: Are their loved ones alive?"

Israel's Justice Ministry declined to comment.

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Ms. Malinovsky, the opposition lawmaker, said she believes that senior Israeli officials feared that pursuing the cases could intensify public scrutiny of the failures by the government and military or undermine negotiations to exchange Palestinian detainees for Israeli hostages.

"They don't want that discourse," she said of the government.

The prime minister's office declined to comment on the reasons for the delay in prosecutions. The prison service and Justice Ministry would not provide any information on the detainees.