Brent Sexton, who plays grieving father Stan Larsen, told TV Guide that he and on-screen wife Michelle Forbes (Mitch Larsen) will both reprise their roles.
"The family is back in season two," he insisted. "I'll leave it at that."
Meanwhile, Mireille Enos (Sarah Linden) and Joel Kinnaman (Stephen Holder) will also return for the second season, TV Line has confirmed.
The Shield actress Jamie Anne Allman is expected to reappear as Mitch's younger sister Terry Marek.
In Forbrydelsen, the Danish series on which The Killing is based, only central character Sarah Lund (Sofie Grabol) appeared beyond the first season.
The Killing was officially renewed for a second 13-part run earlier this week. The first season will conclude this Sunday at 9pm on AMC and will air on Channel 4 in the UK in July.
> The Killing star: 'Filming is not fun'
Watch a trailer for AMC's The Killing below: