JERUSALEM (CNN) -- Several Israeli Jewish suspects were arrested Sunday in connection with the killing of a Palestinian teen, Israeli police said.
"Investigation continuing, strong indication a nationalistic incident, Israeli police spokesman Micky Rosenfeld tweeted.
Rosenfeld told CNN that they were Israeli Jews.
Mohammed Abu Khedair's death came after the bodies of three Israeli Jewish teens were found in the West Bank. Israeli and Palestinian officials quickly suspected that it was a revenge killing, and condemned any such actions.
Rosenfeld also tweeted Sunday that police have arrested a "taxi driver from the north who admitted killing the girl Sheli Dadon in Migdal Haemek recently. Background nationalistic." The 19-year-old Jewish girl was killed last month. The suspect is an Arab resident of the Galilee, the Jerusalem Post reported.
Meanwhile, Khedair's American cousin was given house arrest by a court in Jerusalem Sunday after an incident in which his family says he was beaten by Israeli security forces.
Tariq Khdeir was detained at a protest following the death of his cousin. The 15-year-old high school sophomore from Tampa, Fla., he said he was standing around, watching protesters last week when he was accosted.
"I was attacked by police. I woke up in the hospital," Khdeir said as he walked out of court in Jerusalem on Sunday.
It's unclear why the teen is being investigated or what possible charges he might face.
The teen, who had bruising around his eyes, paid bail and was driven away with his parents to serve his house arrest in the Beit Hanina neighborhood.
"They (his attackers) came from the side of me and I tried to run away," he said, adding that he felt much better Sunday.
He will be kept under house detention for nine days, lawyer Ziad Haidimi said after a court session.
If the investigation ends without charges, he can travel back to the United States, Haidimi said. His mother, Suha Abu Khdeir, said the family "definitely" will sue Israeli authorities.
"I'm not really happy" with the court's decision, she said.
Israel's ambassador to the United States told "Fox News Sunday" there will be justice and that excessive use of force is unacceptable.
"I will tell you, from what I understand about the facts of the case, this is not just an innocent bystander who was pulled off of a schoolyard," Ron Dermer said Sunday. "He was with six other people. They were masked. They threw petrol bombs and Molotov cocktails at our police. Three of them had knives, from what I understand.
"That does not excuse any excessive use of force and our Justice Ministry is opening an investigation."
Tariq was visiting his Palestinian relatives in Jerusalem when he was detained on Thursday.
His relatives say he is the young man who appears in two separate videos being held down and beaten by men wearing the uniform of Israeli security forces.
According to his family, Tariq was among the Palestinians protesting in the Shuafat neighborhood over his cousin's killing. But he wasn't involved in the clashes, they say.
"I asked my son, 'Did you throw rocks?' He said no," Tariq's father, Salah Eddeine Abu Khdeir, told CNN.
The two videos, which were posted independently, say the beating occurred on Thursday.
One neighbor shot a video of the beating and distributed it to family and a TV station. Another video was shot from the other side of the street and posted to YouTube.
Relatives watched the video and told CNN that the teen is Tariq Khdeir. Relatives released pictures of the bruised teenager with swelling on his lips and nose.
The men delivered more than 20 blows to the youth over a period of two minutes. He did not appear to be struggling, and police carried away his limp body afterward.
Both videos start after the incident began, and it's not clear why Khdeir was attacked.
Palestinians have long complained of rough treatment by the Israeli police and double standards when it comes to justice, said Bill van Esveld of Human Rights Watch.
"The concern is that we've got plenty of evidence that this child of 15 was brutally beaten by Israeli law enforcement," van Esveld told CNN. "And instead of the law enforcement officials responsible for the beating being questioned and detained, the child who is the victim is being questioned and detained."
U.S. State Department spokeswoman Jen Psaki called the reports "troubling" and called for a "speedy, transparent and credible investigation and full accountability for any excessive use of force."
CNN's Kareem Khadder and Ben Wedeman reported from Jerusalem; CNN's Steve Almasy reported from Atlanta.
™ & © 2014 Cable News Network, Inc., a Time Warner Company. All rights reserved.