The ex-boyfriend of a dentist whose body was found in a suitcase deliberately killed himself by crashing his car into a truck just hours after speaking with police who were desperately trying to find her.

Harshwardhan Narde, 34, died in a fiery crash on the New England Highway in NSW on Monday, a day after Preethi Reddy, 32, vanished from Sydney's CBD.

Police said Narde and Dr Reddy spent Sunday together in a hotel room before it is believed Dr Reddy was murdered.

Her body was found stuffed inside a suitcase in the back of her Volkswagen Golf in Kingsford on Tuesday night. She had been stabbed multiple times.

Police confirmed Narde was a suspect in Dr Reddy's murder and they were 'not looking for any other persons of interest'.

Friends said the pair met seven or so years ago and Dr Reddy was clear she didn't want to see him anymore when they broke up.

Detectives are investigating whether he went to the conference just to meet with her in the hopes of getting back together.

Others dentists said they saw them happily chatting for some time after the conference ended on Saturday night.

At Oasis Smiles Dental Clinic in Tamworth posted a tribute to Narde, saying he was 'beloved'.

We will miss him beyond words. He touched many people's lives and we will always remember him with his big cheeky smile.

We have been inundated with love and support in which we couldn't be more grateful at this time.

Detective Superintendent Gavin Dengate said that telling Dr Reddy's parents she was dead was the 'toughest thing you can ever do'. He told reporters on Wednesday;

I have goosebumps talking about it. 'As a parent, the worst thing we can do is bury our kids. It's a space no of us want to be in.

Police said her car, a 2016 grey Volkswagen Golf Comfortline registration DFP78P, was a crucial piece of evidence.

TIMELINE TO MURDER

Saturday, March 2

7pm:  Preethi Reddy leaves a dental convention in St Leonards on Sydney's north shore.

Sunday, March 3

2.15am: Dr Reddy is seen at a McDonald's on George Street in the Sydney CBD.

She stayed at a hotel on Market Street in the Sydney CBD with a man known to her.

11am: Dr Reddy last spoke to her family, telling them she planned to head home after having a late breakfast.

Dr Reddy's family report her missing later on Sunday night.

Monday, March 4

10pm: The man Dr Reddy stayed with died after driving his BMW into a deliberate head-on crash with a truck.

Tuesday, March 5

9.30pm:  Her body is found stuffed inside a suitcase in the boot of her grey Volkswagen Golf on a street in Kingsford.