Didi’s Hitch carpooling service apologized again for insufficient safety standards in a Monday letter reflecting on the findings of its internal investigation, which began last year after two passengers were murdered by drivers within the span of a few months.

Zhang Rui, the current head of the suspended service, said the team failed its obligations to users by not recognizing the complexity of offline carpooling. Zhang said Hitch is still undergoing changes as required by regulators, and as yet there is no timeline for its relaunch. The controversial service was taken offline last September, after the second female passenger was murdered by her driver.

Zhang proposed five measures to revamp the product: restricting drivers' routes, abandoning the platform’s social features, more strictly screening new drivers, allocating safety complaints to specialists and improving emergency management.

A government-led investigation into the ride-hailing app last November uncovered multiple threats to passenger safety, according to a report by the country’s Ministry of Transportation in November.

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