Monaco and Horodyshche, Ukraine —  

When the blast went off, Vadym Yermolaiev’s mind went blank. For a split second, he thought his electronic keys might have exploded in his hand. But then he saw his partner splayed out on the steps, wounded. His 13-year old son waving his bloodied arms. Panic set in.

On Monday June 29, a bomb exploded on the doorstep of Yermolaiev’s luxury apartment in Monaco, gravely injuring the Ukrainian millionaire and shocking residents of the wealthy city state.

The suspect, initially described by investigators as a “male” in a “black bucket hat,” vanished. Three days later, the person authorities in multiple countries now say was the attacker was revealed to be Anastasiia Berezovska – a Ukrainian woman with a large snake tattoo on her arm.

She had no criminal record, no known link to Yermolaiev, and no obvious motive. A week after authorities said she planted the bomb, the 39-year-old single mother was found dead, buried in a shallow grave in a forest near Kyiv.

By retracing Berezovska’s footsteps, finding witnesses and hearing from one of the men accused of killing her, CNN has uncovered a tale of violence, strange twists and unanswered questions.