The Central Narcotics Bureau (CNB) depends heavily on technology today. But when it was set up in the early 1970s,many homes did not have telephones, so if an officer was recalled in the middle of the night, a colleague would drive to his village to get him.
Even when off-duty, officers had to check in regularly.
Former senior staff sergeant Kandasamy Renganathan, 68, recounted to The Straits Times: "We had to call the hotline every hour to find out if there was any recall.
"We would go to a public telephone to call the hotline and ask: Any message?"
With drug abuse rampant, pioneer CNB officers also faced a challenging work environment.
Former senior station inspector Lee Cheng Kiat, 70, said: "There were a lot of opium and morphine dens in the Chinatown, Sungei Road and Beach Road areas. There were also cannabis abusers at the time."
Mr Kandasamy added: "We used to raid the drug dens and the doors would be very heavily reinforced, so we had to break them down using crowbars and sledgehammers."
But getting into the hideouts was the easy part.
"By the time we whacked the doors and went in, everyone would have run," said Mr Lee. "There were a lot of shophouse rooftop chases. Left behind in the dens would be the smoking pipes and other drug paraphernalia."
Mr Kandasamy said: "You could even see old people running up to the rooftops."
The duo joined the CNB in 1972, a year after it was set up. Mr Lee recalled one case the following year in which CNB officers following a drug trail were led to a heroin processing lab in China Street. "Brown clumps of what looked like mud were being dried on a piece of cloth on a bamboo tray."
High-speed car chases in rural areas like Lim Chu Kang were also common. One bust uncovered 40 slabs of opium, each weighing 2kg, hidden beneath sawdust in a pig pen.
Officers also clocked long hours.
"On many occasions we just didn't go back home for three to four days," said Mr Lee. "Sleeping in the office was very common ."
The officers' work entailed conducting surveillance and investigations, making arrests and preparing court papers. They also gave drug education talks at schools.
"As the population grew more educated, we had to be more tactful in dealing with people. They also knew their rights," said Mr Kandasamy.
Despite an increasingly liberal attitude towards drugs among today's youth, Mr Lee advised: "Don't ever try drugs because you never know, once you are hooked, the miseries you will cause to your loved ones and yourself."