A man who stalked and killed his former girlfriend was reported to police by 13 other women after he was charged, it has been revealed.
Michael Lane, of Portslade, was jailed in March for the murder of Shana Grice.
The IPCC is looking at the 19-year-old's contact with police about Lane's unwanted attention before she died.
Sussex Police revealed 13 other women had come forward as it accepted six recommendations from the watchdog to improve the way it deals with stalking.
They include asking the force to improve training and data systems, and make better use of relevant information.
The IPCC's associate commissioner Tom Milsom said Sussex Police had shown a positive response to the recommendations and said: "Stalking and harassment are serious offences and in certain situations, such as those involving Shana, can have tragic consequences."
Det Supt Jason Tingley, from Sussex Police, said additional training had already been provided and said: "We have improved our understanding of what stalking and harassment is and what our response should be."
He said Deputy Ch Con Bernie O'Reilly had previously extended his sincere sympathies to Miss Grice's family and friends and had personally visited her family within days of her death.
All reports made by the 13 young women were discussed with the Crown Prosecution Service, officers said.
Police said all the reports related to a three-year period before the murder, apart from one which related to contacts over 10 years.
In some cases there was no evidence of a criminal offence, in others the person did not wish to support a prosecution, and in others the six-month limit for starting action in magistrates' courts had expired.
The force said matters were reported in confidence and it was inappropriate to discuss the individual cases or their outcomes.
Twelve members of staff at Sussex Police have been identified as subjects of the IPCC's ongoing inquiry.