If one is not careful, a large amount of information on him/her can be found online. That's probably the first thing investigators use. They might even hack into your computer or online databases to get information.

They can then try to use connections to find information through the public registry (Pendaftaran Negara) or other records (insurance, bank accounts, employer's database, utilities)

They could also (discreetly) interview/listen to your friends, colleagues, family members, bankers, barbers, clients to know more.

Apart from that, they might also tap into telephone lines to listen to telephone conversations. They might plant cameras, microphones, GPS tracker on your vehicle, clothes, phone, watch, pen etc.

They could also shadow you by following you wherever you go and then investigating your contacts.

maybe you are not interested,but

in Malaysia, investigators do their jobs by finding leads. without leads, there is nothing they can do. if they cannot find leads now, they will wait for another case to come up and try to match with the crime that is being investigated (provided its still not closed).

there is no such thing as finger print or DNA database over here.

If one is not careful, a large amount of information on him/her can be found online. That's probably the first thing investigators use. They might even hack into your computer or online databases to get information.

They can then try to use connections to find information through the public registry (Pendaftaran Negara) or other records (insurance, bank accounts, employer's database, utilities)

They could also (discreetly) interview/listen to your friends, colleagues, family members, bankers, barbers, clients to know more.

Apart from that, they might also tap into telephone lines to listen to telephone conversations. They might plant cameras, microphones, GPS tracker on your vehicle, clothes, phone, watch, pen etc.

They could also shadow you by following you wherever you go and then investigating your contacts.