Prosecutors have been formally asked to consider criminal charges against two Metropolitan police officers alleged to have been involved in the taking of photographs at the scene where two sisters lay dead. The police watchdog announced on Thursday that the Crown Prosecution Service had been sent files of evidence following the deaths of Nicole Smallman, 27, and Bibaa Henry, 46, in June. The pair were found stabbed to death in Fryent country park in north-west London, having been reported missing after a birthday party in the park. The Guardian revealed that month that two Met officers had been arrested on suspicion of misconduct in public office for allegedly taking photos at the scene and then sharing them. The Independent Office for Police Conduct (IOPC) said on Thursday that the investigation had expanded and that another six Met officers were under investigation for receiving photos in a WhatsApp group and failing to report them. The IOPC said the six officers facing investigation for possible disciplinary offences were alleged to have been “either aware of, received or viewed the inappropriate photographs and failed to challenge or report them”. The incident has triggered a series of investigations by the police watchdog. It said it was now investigating the alleged taking of another “inappropriate” photo at the scene of a death and claims that it was shared, as well as discriminatory language and other incidents. The IOPC said: “Other investigations which stem from, but are not connected to the original investigation, continue. These examine allegations officers shared or utilised answers prior to a police exam, the use of discriminatory language, and an allegation one officer took an inappropriate photograph at the scene of a sudden death and subsequently shared it. These investigations are examining potential breaches of honesty and integrity, and equality and diversity. IOPC investigators continue to gather and analyse the evidence.” Smallman and Henry were the daughters of a pioneering cleric, Mina Smallman, the Church of England’s first female archdeacon from a black and minority ethnic background. The sisters were reported missing after a birthday gathering on 5 June, and their bodies were found on 7 June. Police said several days later that they had been stabbed to death by a stranger. Smallman was a freelance photographer. Henry was a social worker and mother of one. The two Met officers facing criminal investigation were arrested by IOPC investigators and have been bailed. In total, the discovery that photos were allegedly taken at the scene has led to 13 Met officers from north-east London being placed under investigation. The IOPC’s regional director for London, Sal Naseem, said the inquiries had led the watchdog to make urgent recommendations to the Met about the force’s culture. Naseem said: “These seek to ensure that police officers, their supervisors and senior management teams all take responsibility for a culture that is in line with the police code of ethics and where inappropriate behaviour can be openly challenged. “Last month we also referred one strand of our investigation to the Crown Prosecution Service as the evidence we have gathered indicates a criminal offence may have been committed. A report has also been sent to the Metropolitan Police Service to consider its next steps in terms of potential disciplinary proceedings for the two officers. “Uppermost in our mind remain the family of Nicole and Bibaa, and we continue to provide them with regular updates. We also ensure the officers involved are aware of developments in our investigation.” Mina Smallman has criticised the culture of the Met and claimed that racial stereotyping played a part in the case. She believes police were too slow to act when her daughters were reported missing. The Met’s response to the two women being reported missing is also under investigation by the IOPC, and it said it had placed one officer under investigation. The watchdog said: “Our separate investigation into how the MPS handled a number of calls from the family and friends of Nicole Smallman and Bibaa Henry who were concerned about their whereabouts between 6-7 June remains ongoing. One officer has been informed that their conduct is under investigation following an indication they may not have progressed these reports appropriately.” The Met commissioner, Cressida Dick, has apologised for the alleged actions of the two officers, which she said left her “dumbfounded”. A man has been charged with the murder of the two sisters.