Tokyo police Monday rearrested a South Korean man already in custody for the alleged murder of his ex-girlfriend in Setagaya Ward, on suspicion of repeatedly stalking her and trespassing into her home prior to her killing.

Investigators allege that the suspect, 30-year-old Park Yong-jun, repeatedly went into the entrance and hallways of the apartment building where the victim, 40-year-old Bang Ji-won, lived in Tokyo’s Minato Ward. He allegedly made seven intrusions over two days from Aug. 29.

Park is also accused of sending eight messages — saying “I’m sorry” and “Thank you,” among other similar messages — to Bang on messaging app KakaoTalk between Aug. 29 and Sept. 1, as well as lying in wait for her about five hours before fatally attacking her in the grounds of her workplace in Setagaya Ward on Sept. 1.