Johannesburg - Investigations in the Molemo Jub Jub Maarohanye case were improper and unfair, the Protea Magistrate's Court heard on Monday.
Defence lawyer Ike Motloung said the police had kept urine samples in a locker for 10 days before they were sent to a laboratory.
He said a cellphone allegedly used to take a video of the cars racing was sent to a corner shop, instead of a police support centre, to open the footage.
Former Protea police station commander Moses Segapo was also "choosy" in taking statements.
Statements
Motloung said Segapo first listened to what was being said and if he did not like what he heard, he did not take a statement.
Segapo earlier told the court he had listened to a statement by two boys who were allegedly in the cars that ploughed into a group of schoolchildren, killing four and injuring two.
Segapo said this was so he could have a better understanding of what was being said before he wrote it down.
He said he could not obtain a statement from the two boys because he suspected they had been coached on what to say.
Motloung put it to him that the manner in which he obtained statements was incorrect.
Maarohanye and his co-accused Themba Tshabalala were allegedly drag-racing when one of their Mini Coopers ploughed into a group of schoolchildren in Mdlalose Street, Protea North in Soweto, on March 8, 2010.
They face charges of murder, attempted murder and driving under the influence of drugs and alcohol.
The trial continues.
Defence lawyer Ike Motloung said the police had kept urine samples in a locker for 10 days before they were sent to a laboratory.
He said a cellphone allegedly used to take a video of the cars racing was sent to a corner shop, instead of a police support centre, to open the footage.
Former Protea police station commander Moses Segapo was also "choosy" in taking statements.
Statements
Motloung said Segapo first listened to what was being said and if he did not like what he heard, he did not take a statement.
Segapo earlier told the court he had listened to a statement by two boys who were allegedly in the cars that ploughed into a group of schoolchildren, killing four and injuring two.
Segapo said this was so he could have a better understanding of what was being said before he wrote it down.
He said he could not obtain a statement from the two boys because he suspected they had been coached on what to say.
Motloung put it to him that the manner in which he obtained statements was incorrect.
Maarohanye and his co-accused Themba Tshabalala were allegedly drag-racing when one of their Mini Coopers ploughed into a group of schoolchildren in Mdlalose Street, Protea North in Soweto, on March 8, 2010.
They face charges of murder, attempted murder and driving under the influence of drugs and alcohol.
The trial continues.