Thamil Prabakaran, a 24-year-old Tamil Nadu resident, was deported this evening, police spokesman Ajith Rohana said.
"He was sent back on the Chennai flight which left at 6.40 pm (local time)," Rohana said.
Prabakaran was earlier handed over to immigration authorities after being questioned by the police's Terrorism Investigation Division.
After the questioning, all the footage shot by Prabakaran was deleted. "As such there was no reason for him to be prosecuted," Rohana said.
Authorities claimed the arrest had thwarted a plot to "carry out disinformation against the country".
He had shot film of a military camp, a road and buildings devastated during the ethnic war. Police said Prabakaran had arrived in Sri Lanka on a tourist visa and had violated visa rules.
Local media described him as a LTTE sympathiser.
Kilinochchi was the administrative center of the Tamil rebels until January 2009, when Sri Lankan forces recaptured the city.
