The mystery surrounding Aarushi Talwar murder case continues to haunt the Central Bureau of Investigation and today it has come a full circle and is back to where the Uttar Pradesh police left it off.

The case commenced with the UP police blaming Aarushi's  parents -- Rajesh and Nupur Talwar -- for the murder, and when one looks at Wednesday's court verdict, it is again back to square one.

There were various scientific tests conducted in this case and each one came out with a different version.

However, CBI officers investigating the case say that the biggest drawback was the missing murder weapon which till date has not been recovered.

The investigators also claim that there were various angles to this case and hence they were unable to come to any conclusion.

Now, with the court ordering that the parents of Aarushi be made accused in this case, the legal battle is going to be a long drawn one.

The legal team of the Talwars say that they will challenge this order. They further add that they cannot reveal much on this at the moment and still studying the order.

The CBI, which had initially said that there was no evidence against the Talwars, have their battle cut out.

The first point of contention is the recovery of the weapon.

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Explains senior advocate C V Nagesh, who specialises in matters of crime, says, "The non recovery of a weapon is not fatal to the case. In such an event one always has to rely upon circumstantial evidence. The prosecution and the investigating agency will now need to form a chain and the weapon is part of this. Now that the weapon has not been found, it may have broken this chain but that is not sufficient to give anyone a clean chit."

"The motive needs to be proven. The prosecution will first have to explain to the court as to who had the motive. The next line of argument would be that the bodies were found inside the house and the second thing is that the bloodstains were wiped from the scene of the crime," he noted.

"The CBI will argue that no other person had access to the house since it was locked from inside and only the occupants were inside the house. At this point the accused will have to explain their stand and convince the court that the crime and the events leading up to it had taken place in their absence," advocate Nagesh said.

"The CBI will then have to put forth before the court that the events leading were within the exclusive knowledge of the accused persons who were present inside the house. The CBI will need to build up this chain leading up to the event and then rely on the circumstantial evidence in order to unerringly prove the guilt of the accused persons," he added.

Many a time the CBI has also towed the line of the Noida police in this case. There are many things mentioned by the CBI which point the finger of suspicion towards the parents, which will now have to be argued before the court.

At one point of time it was argued that there could have been a possible angle of rape in this case, since the private parts and the vaginal swabs of the deceased persons had gone missing.

The evidence was wiped out in order to save the family's honour, the investigators had also claimed. The CBI claimed that the doubt was always towards the members of the family, but they were finding it difficult to prove the motive behind this.

However, while both the accused and the CBI gears up to face the court in this case, it may be pertinent to note the amount of confusion there is in this case.

Before the court there are the confessional statements of the Talwars, and domestic helps Rajkumar and Shambu. Each one had something diagonally opposite to say.

The first of the scientific tests and the confessions was conducted on Rajkumar, who was a domestic help at the residence of Anita Durani, a family friend of the Talwars.

In his confession he stated the murder was committed due to revenge. He stated that Krishna, a compounder at Dr Talwar's clinic, was humiliated and hence he decided to take revenge by killing the doctor's daughter.

"I was invited by Krishna who stayed at a quarter in the Talwar household. We were drinking together and there was another person by the name Shambu. Krishna told us he was insulted by Talwar. Following that Shambu and Krishna went up to Aarushi's room and killed her. Hemraj, a domestic help at the Talwar house, had witnessed this and hence they killed him too," Rajkumar had said.

The next is the confessional statement of Shambu, who also went on to repeat what Krishna had said during the test.

Krishna, however, in another version stated that once Rajkumar reached Aarushi's room he tried to force herself on her. She resisted and in the melee Krishna drew out a dagger and killed her. Hemraj witnessed this and they dragged him to the terrace and killed him.

During this Nupur Talwar was subject to a lie detector test in which she said that her husband had nothing to do with the killing.

"She was God's gift to us and we can't even think of killing her," Nupur had confessed.

Although in all these confessions, there is a mention of a weapon, the fact is that till date the investigators have not been able to ascertain that it was the same weapon that was used in the murder.

Krishna had even confessed that he had hidden the weapon near the scene of the crime, but the CBI was never able to find it.

However, a couple of months after the confession, they did manage to find the weapon, but the forensics have not yet been able to ascertain that it was the same weapon which was used to murder Aarushi and Hemraj.