This case was actually about civil forfeiture, not criminal forfeiture.
If it had been criminal forfeiture, they would have had to show the SUV was purchased using drug money proceeds. Instead, they pursued the civil forfeiture path because it has a lower standard of evidence (more likely than not rather that beyond a reasonable doubt). See page 1 of the opinion, which explicitly states the case is about civil forfeiture...https://www.supremecourt.gov/opinions/18pdf/17-1091_5536.pdf)
If it had been criminal forfeiture, they would have had to show the SUV was purchased using drug money proceeds. Instead, they pursued the civil forfeiture path because it has a lower standard of evidence (more likely than not rather that beyond a reasonable doubt). See page 1 of the opinion, which explicitly states the case is about civil forfeiture...https://www.supremecourt.gov/opinions/18pdf/17-1091_5536.pdf)