TEL AVIV—Israeli security services said Sunday they have detained several Israeli youths suspected of throwing stones at a Palestinian woman and killing her, sparking criticism from settlers who say the teenagers have been mistreated.

Aisha Rabi, 47 years old and a mother of nine, was killed Oct. 12 after a stone struck her in the head while she was riding in a car in the northern West Bank near the Israeli settlement of Rehelim.

Israel’s internal security service, known as the Shin Bet, arrested on Dec. 30 three Israeli teenagers in connection with Ms. Rabi’s death, saying they were being investigated “for severe terrorist offenses including murder.” No charges have been filed. Lawyers for the suspects said they had no connection to the woman’s death.

The Shin Bet confirmed the detentions as pressure grew from settlers demanding information about them.

On Saturday night, several hundred people protested the arrests outside Israeli Prime Minister Benjamin Netanyahu’s residence in Jerusalem, accusing the Shin Bet of mistreating the suspects. The youths’ lawyers accused the Shin Bet of keeping the minors in harsh conditions, subjecting them to intense interrogations and withholding legal counsel for a week.