Cases 31 and 33 were two Singaporeans who were diagnosed with the coronavirus on February 6, 2020.
Here are the profiles of the two cases according to the Ministry of Health (MOH).
The 31st case of coronavirus in Singapore is a 53-year-old man who stays in Tampines Street 24.
The 33rd confirmed case in Singapore is a 39-year-old female who does not have travel history to mainland China but had been to Malaysia from Jan. 22 to Jan 29.
There were no obvious links to previous cases, so the MOH handed the data to the police and the Criminal Investigation Department (CID) took on the challenge.
Cases 31 and 33 both attended church, with one saying it was a church in MacPherson, while the other stating that it was a Paya Lebar church.
After some digging by the police, it turns out that those two churches were in fact the same church -- The Life Church and Missions Singapore at 146B Paya Lebar Road.
But that alone was not enough to end the search. They still had not traced who the virus had initially spread from.
This next part would require a lot of interviews, data analysis, and police legwork.
They also talked to the church and found out that the church gives service in Mandarin. Which ultimately set them on the trail of one of the confirmed Coronavirus patients.
They had narrowed down the tracing to before or on January 19. With those parameters in place, they soon found out that Case 8 and 9 (a married couple who are both Chinese nationals) had indeed been at that very same church on the morning of January 19.
Minister for Home Affairs and Law K Shanmugam, during a visit to the CID Command Centre, described the task as "painstaking work" due to the movements over "several days to different places, tracking each one’s movements and then comparing against the movements of the others, and identifying the commonalities".
Their hours have also increased during this period.
And all this while they still had to shoulder their day-to-day tasks as well.
According to Deputy Assistant Commissioner Deculan Goh, Assistant Director of the Specialised Crime Division, CID:
"Although we are doing this on top of our regular crime fighting duties, our officers are stepping up and putting in extra hours to support the national response to the Coronavirus outbreak."
Despite that challenge, CID officers managed to take on the task, draw links between cases, and help uncover a cluster, all in just one day.
Image courtesy of SPF