Luke Evans's new real-life crime drama The Pembrokeshire Murders launched with 6.3 million (33.1%) for ITV last night, according to overnight ratings figures.
The first episode of the three-part series, which is being stripped this week, became the channel's biggest new drama launch since The Durrells in April 2016.
The show follows Steve Wilkins (Evans), a Detective Superintendent investigating two unsolved double murders from the 1980s in a race against time before the serial killer can strike again.
The drama comfortably won its 9pm slot, with BBC One's Traces managing just 1.9 million (9.7%) between 9pm and 9.45pm and Channel 4's 999: What's Your Emergency? pulling in 1.5 million (8.1%).
Elsewhere, the first episode of the new series of Bradley and Barney Walsh: Breaking Dad - delayed from last week due to an address from the Prime Minister - began strongly on ITV with 4.8 million (23.4%) between 8pm and 8.30pm.