Considering the dating of 4500-3500 BCE it will more likely be a Suvorovo Culture sample.
Just at the pace, surely not the best site to quote albeit does not seem to differ too much from the papers I'm reading through on Suvorovo (excluding further comments):
"The Suvorovo culture, also called the Suvorovo group, was a Copper Age culture which flourished on the northwest Pontic steppe and the lower Danube from 4500 BC to 4100 BC.
The Suvorovo culture is entirely defined by its burials. These include kurgans and flat graves. Burials are oriented towards the east or northeast, in a supine position with legs either flexed or extended. Roofs of the burial chambers are often covered with stone slabs or logs.
Typical grave goods of the Suvorovo culture include ceramics both the Gumelnița–Karanovo culture and the Cucuteni–Trypillia culture, and shell-tempered wares that are typical of the steppe.The Suvorovo kurgans are the earliest ones to appear in Southeast Europe Its features are characteristic of cultures on the steppes and forest-steppes further east in Ukraine and southern Russia. In accordance with the Kurgan hypothesis, the Suvorovo culture is evidence of a westward expansion of early Indo-European peoples from their homeland on the steppe."