Query and Echo were these two loyal henchwomen of the Riddler. Both are capable of handling small firearms and have intermediate combat skills. They wear the same costume with black net stockings and a big question mark logo over their chests. Their suits are either green or purple. Query and Echo do not display any personality differences between each other but they can be differentiated by their hair color. Query is blonde (who often wears a police cap) and Echo is brunette (who has a darker skin tone than her partner).
In some issues they are known as Quiz and Query (Query and Probe at one point) who look like twins but it is uncertain if they are of the same characters. Also in the Birds of Prey #74 their names have been switched so Diedre Vance is Echo and Nina Damfino is Query (This is most likely an error made by the publishers).
Diedre Vance and Nina Damfino (Their real names are never mention in the comics) were once employees of Pandora's Box, an underground dominatrix club, before banding together as two biker women robbing small convenience stores. One night, as they attempted to rob a store, they bumped into an unfortunate customer and forced him to surrender the goods. The customer was none other than the Riddler who too was breaking in at the same store. The Riddler was just starting his criminal career and was looking for thugs for hire and after seeing these two "kindred souls", he immediately hired them. He named them Query and Echo.
First Professional Criminal Career
Their first professional robbery with the Riddler was at the Reservoir Street Cash Depository of Gotham City. It was a warehouse of money with highly sophisticated vaults and security system. The locks were pressure sensitive, meaning that the inside of the vault was an airless vacuum and outside the vault was filled with water. The vault could not be opened until both sides had equal pressure, but fortunately for the Riddler, he broke into the vault the easy way- by sabotaging it. The gang escaped through the sewers with the cash but was confronted by Batman. Both Query and Echo were separated after a rough fight with the Dark Knight but later regrouped in the Riddler's hideout.
The Riddler's next attempt was to steal valuable violins and violas from a mogul who collected them and stored them in his mansion. The Riddler threatened the mogul to give him the cash he desired at a specific location. Query and Echo were sent to collect the money but it turned out to be a trap. The mogul at the collection point was none other than Batman in disguise who apprehend the girls before they could escaped. Batman then tracked down the Riddler to an opera house and arrested him as well.
Query and Echo appeared again in Detective Comics #705- 707. The girls were sent to release a prisoner from a local jail and was presumed to be the Riddler. It later turned out to be false as the Riddler was not in jail but in a hospital due to an arm injury (which he inflicted himself). The person they were after was Arthur Brown, aka the Cluemaster, and Query and Echo managed to spree the Cluemaster out of prison and escaped. Meanwhile, the Riddler made a daring escape out of the hospital and regrouped with the girls.
The Cluemaster (who didn't want to be rescued) had some rivalry with the Riddler and thought that he was going to be killed. The Riddler confessed that he never saw the Cluemaster as a competition but either way, he still wanted to dispose of him just to gain monopoly in the world of puzzles. Later that evening, both Batman and Robin found the Cluemaster on the street and he was rigged with twenty pounds of semtex plastic explosives. The bomb was remote controlled and would detonate if the Cluemaster would disobey the Riddler's instructions. With an ear piece, The Riddler sent cryptic clues to the Cluemaster which he had to guide Batman in various directions. This was to keep Batman and Robin misinformed while the Riddler, Query and Echo made an attempt to steal valuable merchandises at a baseball store. However, the Riddler's foiled and soon enough, he was confronted by the Dark Knight once again. Batman knocked the puzzle trio out cold and sent them back to prison along with the Cluemaster.
Continuation and Additional Info
Query and Echo have since made very few appearances, mostly mention through flashbacks. They seem to no longer have any ties with the Riddler ever since his retirement from crime and are likely to be independent. However, they still wear their respective costumes and still refer to their given names.
Query and Echo made a short comeback in the DC Comics: Origins Card game created by Upper Deck Entertainment. Their card number is DOR-076.
DC Universe Online
Query and Echo make a small apperance in the game DC Universe Online in the Riddler's secret hideout in the Monarch Playing Card Company, Echo and Query assist the hero in defending the Riddler from Deathstroke, who was employed by the Joker to kill him.