Following two separate investigations, PC Charlotte Kaill and PC Bethany Fuller were found to have “deliberately and knowingly” misused the system.
Ms Kaill was sacked, following a misconduct hearing, and Ms Fuller was told she would have been dismissed, if she had not resigned at an earlier date.
South Yorkshire Police said both officers had received training which clearly explained the secure record system, called Connect, should only ever be used for “a lawful policing purpose”.
Police constable Inderjit Bassi was also dismissed for misusing the system, following a misconduct hearing in May, but the force said it cannot reveal all the findings of its investigation yet.
Concerns about PC Kaill’s behaviour were raised six months after she joined the force as a student officer, in July 2019, when the Counter Corruption Unit found she had carried out a number of checks on cases involving her relative.
In that month, officers visited her house to arrest him, even though she had previously told the force’s Vetting Unit that she did not know where he lived because they had fallen out.
She then used the computer system to search for a relative on five separate occasions between August 2019 and September 2020 and opened four court warrants.
During another incident, in September 2020, the officer was off duty when she checked his record, after he had been arrested on suspicion of coercive and controlling behaviour and criminal damage, and conducted a search for the alleged victim.
The police constable then opened her relative’s personal record on another seven occasions over the course of that month, and repeatedly looked into one case, which involved allegations of stalking and assault.
When interviewed, the officer admitted she had conducted a number of checks without a legitimate policing purpose.
PC Kaill said she wanted to find out what her relative had done, after he was arrested at her home, and reassure her mother, but the officer also claimed she did not pass on any information to him or intervene in the investigations.
In her ruling, Chief Constable Lauren Poultney said: “It is a particularly serious aspect of this matter that PC Kaill engaged in repeated acts of misconduct, involving a number of individuals over a sustained period.
“She has repeatedly shown scant regard for the principle that sensitive and confidential data should only be accessed for a proper policing purpose.
“It is also significant that PC Kaill’s computer misuse began very shortly towards the end of her tutor period when she would have been under less intense supervision."
She added: “In my judgement the only appropriate outcome is one of dismissal without notice.”
A separate investigation found Ms Fuller opened a record of a domestic abuse investigation, in which her relative had been named as the suspect, while she was at home on study leave.
It happened in September 2021, just seven months after she joined the force as a student officer.
When the police constable was interviewed, she claimed she had not done anything wrong and did not realise her relative would be on the police system.
In her written decision Chief Constable Poultney said: “Former PC Fuller was, I find on the evidence, well aware by virtue of her training that she was engaged in wrongdoing and I do not accept her assertions to the contrary.
“In any event, it would be deeply troubling for former PC Fuller to deliberately and purposefully access sensitive police data regarding a close family member without a proper policing purpose and not consider that she had engaged in any misconduct.
“The public expect that sensitive data held by the police will be accessed and used only for proper policing purposes and accessing such data improperly involves a fundamental breach of the public’s trust in police officers.”