There was a buzz in the night sky as a flash of green zipped over a forested area in Bukit Panjang. The unmanned aerial vehicle (UAV) circled the area for nearly an hour.
On the ground, two men watched images on screens while manoeuvring the drone remotely.
They were not your ordinary drone enthusiasts, but men in blue on a mission last Wednesday night to find any illegal immigrants who might have been hiding in the thick vegetation surrounding Bukit Timah Expressway (BKE).
Based on intelligence received, the police had raided a hideout under a section of the BKE earlier that night. They arrested five men suspected to be immigration offenders from Indonesia, and seized a large amount of contraband cigarettes.
A drone was then sent in to scan the area and detect any runaways.
The use of drones is part of an ongoing trial by the Singapore Police Force to see how technology can complement police operations.
Since 2016, the police have been testing UAVs for traffic management and crowd monitoring. They have previously deployed drones during large scale events like the Marina Bay Singapore Countdown earlier this year.
The police are looking into expanding the use of drones, which could save time and manpower in certain situations. The force had also said that drones can be used for search and rescue, hostage situations and public order incidents.
A drone that is equipped with thermal-imaging capabilities enables the police to quickly spot people in a forested area.
On a screen attached to the drone's remote control, a person shows up as a red figure due to his or her body temperature, while a cool forest appears blue.
Wednesday's drone operation - which was witnessed by the media - took about an hour. No runaway was detected.
The arrest of the five suspects was part of a five-day enforcement operation led by the police and supported by agencies such as the Central Narcotics Bureau, Immigration and Checkpoints Authority, Singapore Civil Defence Force and Singapore Customs.
The operation, which ended on Friday night, covered multiple locations in the western and northern parts of Singapore, including Tuas, Jurong West, Choa Chu Kang, Bukit Batok and Woodlands.
A total of 125 people - 62 men and 63 women - aged between 18 and 62 were arrested, said the police in a statement yesterday.
A total of 4,332 packets of duty-unpaid cigarettes were seized. The total duty and goods and services tax evaded amounted to $43,980 and $3,190, respectively.
Assistant Commissioner Devrajan Bala, Commander of Jurong Police Division, thanked officers from the division and various agencies for their support and collaboration.
He said: "This joint operation is part of police's continuous efforts to clamp down on criminal activities. While the police work closely with other Home Team and law enforcement agencies to deal with those who take part in illicit activities, we also urge the public to be vigilant and not fall prey to crime."
The suspected offences of those arrested include vice-related activities in residential units, employment-related offences at public entertainment outlets, e-commerce scams, loansharking activities and immigration-related offences.
Investigations are ongoing.