Police are continuing to unravel the mystery of Paul Meyer's rampage that left seven people dead before he took his own life.

While family and friends of Rosanne Lamb, 19, Rudi Niemann, 53, Cindy Jeffrey, 21, and her mother Linda van Rooyen - killed on Wednesday - attend their funeral on Monday, a postmortem will be conducted on Meyer's body in the Kroonstad mortuary in the Free State.

Police have not yet established what caused Meyer, 35, to "snap" but it appears he was leading a double life - living with his wife Adriana and their daughters Monica, nine, and Vicky, four, in a Delarey flat, and with Jeffrey, his pregnant fiancée, in a shared house in Albertville.

It appears Meyer spent his nights at the Delarey flat, telling his wife he was working during the day - and spent his days with Jeffrey, who believed he was working night shift.

But, with two families to support and no work, the lies and bills piled up.

On Wednesday, Meyer shot Jeffrey, her mother and co-tenants Lamb and Niemann after asking the domestic worker to go and buy formula for Lamb's baby, four-month-old Ricardo.

Only the baby survived the attack.

That night, Meyer fetched his wife and daughters and booked the family in at the Robertsham Hotel, calling himself Niemann.

The next morning Meyer shot his wife and daughters while they slept and fled.

The bodies were found on Thursday afternoon.

On Friday, police tracked Meyer down while he was sitting in his car on the north bank of the Vals River in Kroonstad. He shot himself and was declared dead on arrival at Boitumelo Hospital.

Police spokesperson captain Schalk Bornman said the blood-stained 357 magnum, the firearm Meyer shot himself with and the only gun in the car, would be sent for forensic tests to see whether it was the same weapon used in the murders.

Bornman said this could "take quite a bit of time".

Once the postmortem results are available, they will be entered into the centralised murder dockets and forwarded to the inquest court where a decision on how to proceed with the case will be taken.

Bornman said the task team established to track Meyer would continue its investigations, recording different versions given by close friends and relatives of the deceased to try to establish why a man with no history of violence would go on a murderous rampage.

Meanwhile, baby Ricardo has been taken to a place of safety after several people tried to claim custody of him. A family friend said Rose Lamb, Rosanne's distraught mother, intended to look after the baby.

Meyer will be buried with his wife and daughters.