On Feb 25, a sport utility vehicle laden with explosives was found 500m near Antilia, the 27-storey US$2.2 billion (S$3 billion) house in Mumbai belonging to Asia's richest man Mukesh Ambani.
A bomb disposal squad, alerted by Mr Ambani's security, found 20 sticks of blasting gelatin and a note addressed to Mr Ambani, the 63-year-old chairman of Reliance Industries, and his 57-year-old wife, Neeta.
The explosives, which were not rigged up, appeared to be a threat.
The note said "this is a trailer", but warned that the explosives would be connected next time. "We have made arrangements to blow up your entire family," the note reportedly said.
Investigations have led to the shocking arrest of suspended assistant commissioner of police Sachin Vaze, a former sharpshooter who was part of the probe into the Ambani bomb case before he was held as the prime suspect.
The car belonged to Mumbai businessman Mansukh Hiren, 46, who told the police it had been stolen on Feb 17.
Shortly afterwards, the body of Mr Hiren, who investigators suspect gave the car keys to Vaze, was found washed up in a Mumbai creek, with his face covered by a mask and mouth stuffed with handkerchiefs, according to Indian media reports.
It is a sensational crime mystery involving Asia's richest man, a corrupt cop and more plot twists than a Bollywood film.
Through CCTV footage, call records and the arrest of two other suspects, federal and state investigators believe Vaze, who allegedly knew the murdered man well, is behind both crimes. There is speculation that this is a case of an extortion attempt gone wrong.
Police also think he arranged for a fake number plate for the bomb-laden car.
In the early 2000s, Vaze was part of a team of specialists that Time magazine called "Mumbai's dirty Harries", who were credited with cleaning up the city's mob crime.
Said to have 63 killings under his belt, Vaze left the force in 2004 over a death in custody for which a trial is still ongoing. He was reinstated last year for Covid-19 duties.
Now in custody and charged by the National Investigating Agency (NIA) with an attempt to commit or abet a terrorist act under the Unlawful Activities (Prevention) Act, Vaze has denied all the charges.
In court, he said that he was being "made a scapegoat".
Indeed, there are more questions than answers in the case, and investigators have yet to release any motive for the bomb threat.
Why would a former cop think that he could get away with targeting India's most prominent business family?
"What could be most relevant for us to know is the motive for planting the car with the gelatin sticks and the threatening letter outside Ambani's house," wrote former top cop Julio Ribeiro in The Indian Express.
"Will this matter bring more senior police leaders under the scanner? Why was Vaze reinstated? Why was he given such a sensitive post? Why was he not put on Covid-related duties, on which pretext he was reinstated? These questions need to be answered."
But the story does not end there. A political angle has added another explosive element to the mystery.
Former police commissioner Param Vir Singh, who was transferred from his post on the back of this case, has accused Maharashtra state Home Minister Anil Deshmukh of graft, alleging that he got police officers like Vaze to collect illegal money from businesses.
Mr Singh has filed a case in the Bombay High Court asking for a federal investigation into the corruption charges against the Home Minister.
Mr Deshmukh has denied the allegation even as a political fight has broken out between the Shiv Sena, which heads the local government, and the Bharatiya Janata Party (BJP). The two one-time allies have turned bitter enemies, with the BJP gunning for the Shiv Sena government.
Many believe the case is about more than just crime.
"The revelations are testimony to the police-politician nexus," noted Mr Mohan Guruswamy, an Indian analyst.
Still, even former Mumbai cops say this is a rather unusual case.
"It is a rare case. I am sure that NIA, being a highly professional investigating agency, will be able to find out the culprits in the Antilia and Mansukh Hiren cases," said Dr Meeran Chadha Borwankar, a retired officer of the Indian Police Service and the first woman to head the Mumbai crime branch.
"My only concern is that the trials should be prompt as long delays and pendency in courts have made citizens lose faith in the criminal justice system in India."