A DNA database could help reduce investigation time and is also important because of the high rate of repeat offenders, said geneticist Dr Carolyn Hancock.
"Research indicates that 90% of rapists are repeat offenders and 50% of armed robbers are also repeat offenders," she said.
"Research in the UK indicates that when criminals are confronted with DNA evidence, 80% of them plead guilty and this could save an enormous amount of court time."
Hancock said DNA samples are taken from body fluids like semen, saliva and blood, tissue and hair.
"The DNA will only be analysed at 10 places - none of which reveal any information about a person."
She said identical twins shared the same DNA but not the same fingerprints.
"DNA is not the only form of evidence used to solve crime so fingerprints would help identify which twin committed the crime."
Currently, police take pictures and fingerprints.