Headley got in trouble because of his kids!

Lashkar-e-Tayiba operative David Coleman Headley had made his children do 'military drills' in a Chicago park last summer, according to a law enforcement officer, who said this observation had helped bring the Pakistani-American terrorist 'on the radar'.

"On a summer day last year, Headley, like many fathers, took his children to a Chicago park. There, he ran his children through military drills, including manoeuvres such as rolling into a shooting position," a report in the Chicago Tribune said, quoting the officer.

The manoeuvres had caught the attention of a Chicago police official who, like others in his department, was being trained to be more alert and to document suspicious activities. "At the park, the officer did exactly that," the report said, adding "the officer also took note of the fact that Headley was speaking Urdu."

"This really helped bring him (Headley) on the radar," Chicago police Commander Steve Caluris was quoted as saying of the officer's observation.

"We are not saying he witnessed him plotting something out there in the public. He recognised activity that seemed out of the ordinary," Caluris said.

The observations -- by the officer who had received counter-terrorism training -- became part of the case that was built against Headley, who was arrested by the Federal Bureau of Investigation in October last year and later charged in the 2008 Mumbai terrorist attacks and with planning attacks in Denmark. Authorities did not disclose the name of the Chicago park where Headley was seen.

"The details of his park activities were eventually combined with an independent tip the FBI task force got about Headley, adding pieces to the emerging picture of a possible terrorist," the report said.

A Pakistani-American, Headley was living in Chicago's far North Side in 2009. His plans for an attack in Denmark were under way, the report said.

Headley, who has pleaded guilty to the terror charges and is currently lodged in a Chicago jail, had been successful in avoiding detection despite two of his wives coming forward with information about him.

US officials have said those tips were not specific enough to launch an investigation of a citizen. Headley avoided the death penalty in exchange for his plea and he is expected to testify against co-defendant Tahawwur Hussain Rana in the terror plots. Headley had travelled extensively across India and shared information with his Pakistani handlers about terror targets in Mumbai and other Indian cities.

Officers said while Headley's investigation, on which law enforcement officials worked on 24/7, is a 'success, there are more plots out there to uncover'.

Chicago police investigates some 20 tips on potential terrorist-related activity each week, while more officers are out in neighbourhoods trying to gain contacts and information as part of a counter-terrorism strategy.

The Tribune report said that while terrorism tips can come from anywhere, the 13,500 police officers on Chicago's streets are considered a prime source of information.

"They are the eyes and ears on the street," said Chicago police Sergeant Val Roytman, who oversees the training. "They are the most valuable resource in the war against terrorism."