TAIPEI (Taiwan News) — The CEO of Yunyun Technology and CuboAi is under investigation for the death of the company’s chief technology officer.

The attack occurred at the company’s Taipei office in Xinyi District on Saturday afternoon while the CEO, 52-year-old Thomas Tseng (曾志新), was negotiating the departure of the 51-year-old CTO, surnamed Liang (梁), with the company’s human resources director, reported UDN. After allegedly stabbing Liang, Tseng attempted to take his own life and was critically injured.

As of Sunday, Tseng remained in critical condition at a Taipei hospital under police supervision. Authorities have been unable to question him, per CTI.

Days before the attack, Liang shared a resignation letter with employees criticizing Tseng’s behavior and leadership. Tseng demanded the letter be removed from the company’s online message board, which reportedly fueled tensions.

At the end of the resignation meeting, Tseng moved toward the door as if to leave, then suddenly drew a concealed knife and attacked Liang.

The HR director yelled for help as colleagues rushed in. Unfortunately, Liang had already lost vital signs, and Tseng had stabbed himself before they could intervene.

CuboAi, a successful Taiwanese tech startup, is known for its award-winning smart baby monitors. The company has been the top-selling baby monitor brand in Japan in recent years.