Israeli Ambassador Alon Ushpiz, however, thanked India for the probe into the incident and support it offered to Israel.
"The terrorists who committed this heinous attack and the Government of Iran that sent them, must be made accountable," Ushpiz said in a statement issued.
The attack was carried out on February 13 last year.
"In the days, weeks and months following this terrorist action, we were embraced by a wave of support and friendship from the Government and the people of India. We are grateful for this and for the security that the Indian authorities provide us," the Ambassador said.
Tal Yehoshua Koren, an Israeli diplomat and wife of the defence attache at the embassy, was injured in the car bomb attack that had taken place near the Prime Minister's residence in central Delhi. Israel had immediately blamed Iran for the attack.
Ushpiz said Tal was still suffering from her wounds. An Indian driver of the vehicle which was targeted and two other people were also injured in the attack.
"It is understood that the Iranian authorities did not provide answers to Indian officials who travelled to Tehran to gather information," said the Israeli Ambassador.
During the investigation, role of four Iranian nationals surfaced. It was found that a motorcycle rider had attached a magnetic explosive device to the diplomat's car and sped away. Within seconds, the device exploded, setting the car on fire.
A two-member Delhi Police team was in Iran in August last year to seek cooperation from its counterpart in the probe.
New Delhi: On the eve of the first anniversary of the bomb attack on one of its diplomats here, Israel today said the terrorists who committed the "heinous attack" must be made accountable.
First Published: Tuesday, February 12, 2013, 16:27