Castle creator Andrew Marlowe says he’s “heartbroken” that the decision was made not to bring Stana Katic (Detective Kate Beckett) and Tamala Jones (medical examiner Lanie Parish) back for the series’ ninth season.

Marlowe had always called the Castle/Beckett relationship — aka Caskett — central to the concept of the series. He left the show at the end of last season when Alexi Hawley and Terence Paul Winter were named new showrunners.

Other Castle cast members also spoke out on Twitter. Jon Huertas, who plays Javier Esposito on the series, expressed his shock and also uncertainly about what lies in the future for his character and the series.

Seamus Dever, who plays Kevin Ryan on the series, praised both of his co-workers:

And Susan Sullivan, who plays Castle’s mother Martha Rodgers said she was “surprised and saddened”: